{"gene":"NHERF2","run_date":"2026-06-10T05:19:52","timeline":{"discoveries":[{"year":1998,"finding":"NHERF2 (E3KARP) directly binds NHE3 via its second PDZ domain (plus C-terminal domain), and also binds the cytoskeletal protein ezrin via its C-terminal domain, forming a scaffold that localizes PKA near NHE3 to enable cAMP-dependent inhibition of NHE3.","method":"In vitro binding assays, co-localization in PS120 fibroblasts","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — direct in vitro binding assays with domain mapping, replicated across two papers (PMID:9748260, PMID:9792717) using orthogonal methods (in vitro binding + co-immunoprecipitation + functional NHE3 activity assay)","pmids":["9748260","9792717"],"is_preprint":false},{"year":1998,"finding":"NHERF2 (E3KARP) is not phosphorylated by cAMP/PKA and does not change phosphorylation state upon 8-bromo-cAMP treatment; it functions as an adapter (not a direct PKA substrate) linking NHE3 to ezrin to localize PKA type II near NHE3.","method":"In vivo phosphorylation studies, co-immunoprecipitation in opossum kidney cells","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal co-IP plus in vivo phosphorylation assay in a single lab, two orthogonal methods","pmids":["9792717"],"is_preprint":false},{"year":2000,"finding":"NHERF2 (E3KARP) associates with CFTR preferentially through CFTR's PDZ-binding motif and E3KARP's second PDZ domain with nanomolar affinity; E3KARP also associates with ezrin in vivo, and co-expression of CFTR with E3KARP and ezrin in Xenopus oocytes potentiates cAMP-stimulated CFTR Cl⁻ currents.","method":"Co-immunoprecipitation, confocal microscopy, cell fractionation, Xenopus oocyte electrophysiology","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — nanomolar affinity binding assay, co-IP, functional reconstitution in oocytes, multiple orthogonal methods in single study","pmids":["10893422"],"is_preprint":false},{"year":2001,"finding":"SGK1 specifically interacts with PDZ domains of NHERF2 (but not NHERF1) to mediate glucocorticoid/dexamethasone activation of NHE3; kinase-dead SGK1 blocked NHE3 activation, demonstrating NHERF2 acts as a scaffold linking SGK1 to NHE3.","method":"Co-expression in PS120 fibroblasts and opossum kidney cells, dominant-negative kinase-dead SGK1, NHE3 activity assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — dominant-negative mutagenesis plus functional NHE3 activity assay, replicated in two cell lines with specific NHERF2 requirement demonstrated","pmids":["11751930"],"is_preprint":false},{"year":2001,"finding":"NHERF-2 PDZ domains robustly self-associate (homo-oligomerize) without requiring additional proteins, and NHERF-1 and NHERF-2 form hetero-oligomers in cells via their PDZ domains; NHERF-2 oligomerization is not regulated by phosphorylation (unlike NHERF-1).","method":"Purified PDZ domain association assays, co-immunoprecipitation with differentially tagged constructs","journal":"Biochemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vitro purified protein assay plus cellular co-IP, single lab, two orthogonal methods","pmids":["11456497"],"is_preprint":false},{"year":2002,"finding":"Ca²⁺-dependent inhibition of NHE3 requires E3KARP (NHERF2) specifically (not NHERF1), and occurs via Ca²⁺-dependent association of alpha-actinin-4 with E3KARP through alpha-actinin-4's actin-binding domain plus spectrin repeat domain, leading to NHE3 oligomerization and endocytosis.","method":"Stable transfection of PS120 fibroblasts, NHE3 activity assays, co-immunoprecipitation, dominant-negative overexpression, surface biotinylation","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (activity assay, co-IP, dominant-negative, surface biotinylation), specific domain mapping, single lab","pmids":["11948184"],"is_preprint":false},{"year":2002,"finding":"NHERF2 (E3KARP) binds the DRA (downregulated in adenoma) Cl⁻/HCO₃⁻ exchanger's C-terminal ETKF motif via the second PDZ domain, potentially linking parallel NHE3 and DRA transporters in the apical membrane.","method":"In vitro PDZ binding assays with GST fusion proteins, immunofluorescence co-localization in human proximal colon","journal":"Biochemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vitro binding with domain mutagenesis plus immunofluorescence co-localization, single lab","pmids":["12369822"],"is_preprint":false},{"year":2002,"finding":"Adenosine A2b receptor co-immunoprecipitates with E3KARP (NHERF2) and ezrin upon agonist stimulation; the A2bR is recruited to the plasma membrane and caveolar fractions upon agonist stimulation in intestinal epithelial cells.","method":"Co-immunoprecipitation from T84 and Caco2-BBE cells, confocal microscopy","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — co-IP confirmed in two cell lines but single lab, agonist-dependent interaction demonstrated","pmids":["12080047"],"is_preprint":false},{"year":2002,"finding":"NHERF2 and SGK1 synergize to increase ROMK1 K⁺ channel activity by enhancing channel abundance in the plasma membrane; neither NHERF2 nor SGK1 alone affects ROMK1, but their combination markedly increases K⁺ channel activity and slows decay after brefeldin inhibition.","method":"Xenopus oocyte co-expression, electrophysiology, brefeldin A experiments","journal":"Journal of the American Society of Nephrology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reconstitution in oocytes with electrophysiology, brefeldin A trafficking assay, single lab","pmids":["12444200"],"is_preprint":false},{"year":2003,"finding":"PKCα binds specifically to the PDZ1 domain of E3KARP (NHERF2) in a Ca²⁺-dependent manner; PKCα is necessary for Ca²⁺-dependent decrease in plasma membrane NHE3 (endocytosis) but not for NHE3 oligomerization.","method":"GST pulldown, co-immunoprecipitation, PKC inhibitors, surface biotinylation in PS120/NHE3/E3KARP cells","journal":"American journal of physiology. Cell physiology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — GST pulldown with domain specificity plus cellular co-IP plus functional activity assay, multiple orthogonal methods, single lab","pmids":["12954600"],"is_preprint":false},{"year":2004,"finding":"LPA receptor LPA2 (but not other LPA receptors) specifically interacts with NHERF2 via LPA2's C-terminal PDZ-binding motif and NHERF2's second PDZ domain; NHERF2 indirectly links LPA2 to PLC-β3 forming a ternary complex that specifically activates PLC-β3 and downstream ERK/COX-2 signaling.","method":"Co-immunoprecipitation, PDZ domain binding assays, siRNA knockdown of NHERF2 and PLC-β3, stable NHERF2 expression, inositol phosphate assay","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (co-IP, PDZ mutants, siRNA, functional PLC assay), specific isoform selectivity demonstrated, single lab","pmids":["15143197"],"is_preprint":false},{"year":2004,"finding":"NHERF2 (E3KARP) mediates LPA-induced stimulation of NHE3 by enabling LPA-induced PLC activation and subsequent intracellular Ca²⁺ elevation, which drives exocytic trafficking of NHE3 to the apical membrane in a PKC-independent manner.","method":"PLC inhibitor (U73122), Ca²⁺ chelator (BAPTA-AM), PKC inhibitor, NHE3 activity and surface amount in OK cells stably expressing E3KARP","journal":"Biochimica et biophysica acta","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple pharmacological inhibitors with functional NHE3 activity and surface abundance readouts, single lab","pmids":["15238220"],"is_preprint":false},{"year":2004,"finding":"NHERF2 co-immunoprecipitates with TRPC4 (but not TRPC5) from renal medullary lysates and they co-localize in descending vasa recta endothelial cells and pericytes.","method":"RT-PCR, immunohistochemistry, reciprocal co-immunoprecipitation from renal medullary lysates","journal":"American journal of physiology. Cell physiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal co-IP from native tissue plus co-localization, single lab","pmids":["15590898"],"is_preprint":false},{"year":2005,"finding":"NHERF2 is required for cGMP inhibition of NHE3 (while NHERF1 is not); NHERF2 acts as a novel protein kinase G-anchoring protein, binding cGKII via its PDZ2 C-terminus, and membrane myristoylation of cGKII is additionally required for NHE3 inhibition.","method":"Co-expression in PS120 cells, in vitro NHERF2-cGKII binding, non-myristoylated cGKII mutant, NHE3 activity assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro binding with domain specificity, myristoylation mutant, functional NHE3 activity assay, specific NHERF2 vs NHERF1 selectivity, single lab with multiple orthogonal approaches","pmids":["15722341"],"is_preprint":false},{"year":2005,"finding":"NHERF-2 specifically interacts with the P2Y1 receptor C-terminus via NHERF-2's second PDZ domain; this interaction tethers P2Y1R to PLC-β and prolongs P2Y1R-mediated Ca²⁺ signaling in glial cells; point mutations disrupting the P2Y1R-NHERF-2 interaction attenuate the duration of Ca²⁺ responses.","method":"PDZ domain proteomic array screen, co-immunoprecipitation, confocal microscopy, functional Ca²⁺ signaling assays with point mutants","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — array screen plus co-IP plus functional mutagenesis, multiple orthogonal methods demonstrating mechanism","pmids":["15901899"],"is_preprint":false},{"year":2005,"finding":"Podocalyxin (gp135) and NHERF-2 co-localize at a preapical subdomain in single MDCK cells and in terminally polarized apical membranes; the PDZ-binding motif of podocalyxin is required for this apical targeting, and depleting podocalyxin by RNAi causes defects in epithelial polarization.","method":"Domain deletion mutants, RNA interference of podocalyxin, confocal microscopy in MDCK cells","journal":"The Journal of cell biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — PDZ motif domain mutants plus RNAi with polarization phenotype, single lab","pmids":["15642748"],"is_preprint":false},{"year":2005,"finding":"NHERF2's second PDZ domain is required for SGK1/NHERF2-mediated stabilization of TRPV5 at the plasma membrane; the TRPV5 C-tail interacts with NHERF2 in a Ca²⁺-independent manner.","method":"Pull-down assays, PDZ domain deletion mutants, chemiluminescence surface abundance assay, Xenopus oocyte electrophysiology","journal":"Cellular physiology and biochemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — PDZ domain deletion mutants with functional electrophysiology readout plus pulldown, single lab","pmids":["15665527"],"is_preprint":false},{"year":2005,"finding":"SIP-1/NHERF2 interacts with mouse SRY via the PDZ1 domain (involving an internal SRY domain rather than C-terminus as in human SRY), and both mouse and human SRY induce nuclear accumulation of NHERF2 in cultured cells; NHERF2 and SRY are co-expressed in the nucleus of pre-Sertoli cells during testis determination.","method":"Co-immunoprecipitation/interaction assays, nuclear accumulation assays in cultured cells, GFP-Sry transgenic mice for co-expression analysis","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — protein interaction assays plus nuclear localization experiments and in vivo co-expression, single lab","pmids":["16166090"],"is_preprint":false},{"year":2006,"finding":"NHERF-2 specifically interacts with mGluR5 (not mGluR1a) via NHERF-2's second PDZ domain; co-expression prolongs mGluR5-mediated Ca²⁺ mobilization and potentiates mGluR5-mediated cell death; a single point mutation in mGluR5-CT abolishes the interaction and attenuates these effects.","method":"PDZ domain proteomic array, co-immunoprecipitation, confocal microscopy, functional Ca²⁺ signaling assays with point mutants, cell death assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — PDZ array plus co-IP plus mutagenesis plus functional signaling assays, multiple orthogonal methods demonstrating mechanism","pmids":["16891310"],"is_preprint":false},{"year":2006,"finding":"When NHE3 is co-expressed with CFTR, NHE3 sequesters NHERF2's PDZ2 domain, which prevents PDZ2 from participating in PKA-dependent apical CFTR expression and activation; deletion of NHERF2 binding domains inhibits PKA-dependent apical CFTR expression.","method":"NHERF2 PDZ domain deletion constructs, functional CFTR activity assays in A6-NHE3 cell monolayers","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — PDZ domain deletion mutants with functional CFTR assay, single lab","pmids":["16824484"],"is_preprint":false},{"year":2008,"finding":"NHERF2 (but not NHERF1) specifically enhances PEPT2 function and surface abundance via the PEPT2 C-terminal PDZ-binding motif; NHERF2 stabilizes PEPT2 at the cell surface (demonstrated by dynasore experiments) and acts together with SGK1 which phosphorylates PEPT2 at Ser185.","method":"Xenopus oocyte electrophysiology, surface abundance immunoassay, C-terminal deletion mutant, dynasore endocytosis inhibition","journal":"Cellular physiology and biochemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional electrophysiology plus surface abundance assay plus pharmacological endocytosis block, single lab","pmids":["19088452"],"is_preprint":false},{"year":2009,"finding":"NHERF2 confers inhibitory LPA receptor signaling to CFTR in duodenum; in Nherf2⁻/⁻ mice, FSK-stimulated HCO₃⁻ secretion is augmented, and LPA-mediated inhibition of CFTR-dependent secretion is abolished, demonstrating NHERF2 couples the LPA receptor to CFTR to provide inhibitory signals.","method":"Nherf2 knockout mouse model, duodenal HCO₃⁻ secretion measurements, laser microdissection and quantitative PCR","journal":"The Journal of clinical investigation","confidence":"High","confidence_rationale":"Tier 2 / Strong — in vivo genetic knockout with quantitative physiological readout, confirmed in multiple NHERF knockout models in same study","pmids":["19221439"],"is_preprint":false},{"year":2009,"finding":"LPA stimulates NHE3 and intestinal fluid absorption via the LPA5 receptor, and this stimulation requires NHERF2 which interacts with LPA5; LPA-mediated intestinal fluid absorption is absent in Nherf2⁻/⁻ mice but preserved in Lpa2⁻/⁻ mice; LPA increases NHE3 protein abundance at the brush border.","method":"Nherf2⁻/⁻ and Lpa2⁻/⁻ knockout mice, intestinal fluid absorption measurements, heterologous expression of LPA5 with NHERF2","journal":"Gastroenterology","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic knockout mouse model with quantitative fluid absorption assays plus heterologous reconstitution, multiple orthogonal approaches","pmids":["19800338"],"is_preprint":false},{"year":2010,"finding":"NHERF2 silencing in endothelial cells causes hyperproliferation even without mitogens, associated with increased cytoplasmic calcium, increased c-Myc and cyclin D1, and reduced p27; NHERF2 is thus a negative regulator of endothelial proliferation.","method":"siRNA knockdown, cell proliferation assays, cell cycle analysis, mouse hemangioma model","journal":"Blood","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA knockdown with multiple molecular readouts and in vivo mouse model, single lab","pmids":["22343917"],"is_preprint":false},{"year":2010,"finding":"MAGI-3 competes with NHERF-2 for binding to LPA2 and PLC-β3; NHERF-2 promotes LPA2-Gαq coupling and stimulates PLC activity and cell migration, while MAGI-3 promotes LPA2-Gα12 coupling and inhibits NF-κB/JNK signaling, demonstrating NHERF-2 determines G-protein coupling specificity of LPA2.","method":"Overexpression and knockdown of MAGI-3 in HCT116/SW480 cells, co-immunoprecipitation, migration/invasion assays, inositol phosphate and NF-κB assays","journal":"Gastroenterology","confidence":"High","confidence_rationale":"Tier 2 / Strong — competitive binding, co-IP, and multiple functional readouts (migration, invasion, IP, NF-κB), single lab with multiple orthogonal methods","pmids":["21134377"],"is_preprint":false},{"year":2010,"finding":"NHERF2 binding to NHE3 in brush borders is dynamic; LPA stimulation transiently dissociates the NHERF2-NHE3 complex (loss of co-precipitation and FRET signal at 30 min, re-established at 50-60 min), increasing NHE3 mobility via a PI3K-dependent exocytic pathway and a PI3K-independent dissociation from NHERF2.","method":"FRAP, acceptor photobleaching FRET, co-immunoprecipitation, PI3K inhibitor LY294002 in OK cells stably expressing NHERF2","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 / Strong — FRET, FRAP, and co-IP as three orthogonal methods demonstrating dynamic interaction, pharmacological dissection of pathway","pmids":["20571054"],"is_preprint":false},{"year":2010,"finding":"NHERF2 ablation in murine intestine shifts NHE3 localization from the terminal web to microvilli and abolishes Ca²⁺-ionophore- and carbachol-mediated inhibition of NHE3, as well as STp (cGMP-mediated) inhibition, while forskolin-induced inhibition is preserved; NHERF2 tethers NHE3 near the terminal web.","method":"NHERF2 knockout mice, fluorometric NHE3 activity assay, immunolocalization, knockout validation","journal":"The Journal of physiology","confidence":"High","confidence_rationale":"Tier 2 / Strong — in vivo genetic knockout with quantitative NHE3 activity and localization readouts, independently confirmed in related study","pmids":["20962002"],"is_preprint":false},{"year":2010,"finding":"NHERF2 apical scaffolding enhances apical localization of PMCA2w/b in polarized MDCK cells by anchoring the pump to the apical actin cytoskeleton via ezrin, reducing pump internalization and lateral mobility; PMCA2x/b remains basolateral even with NHERF2 overexpression.","method":"Co-expression in polarized MDCK cells, surface biotinylation, FRAP, cytochalasin D/latrunculin B actin disruption, co-localization with ezrin","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — surface biotinylation plus FRAP plus actin disruption experiments, multiple orthogonal methods in polarized cell system","pmids":["20663896"],"is_preprint":false},{"year":2010,"finding":"NHERF-2 knockdown in astrocytes reduces GLAST glutamate transporter activity and protein half-life; endogenous GLAST and NHERF-2 robustly co-immunoprecipitate; the interaction is dependent on the last amino acid of GLAST's C-terminus.","method":"siRNA knockdown, co-immunoprecipitation with C-terminal deletion mutants, pulse-chase metabolic labeling, glutamate uptake assay","journal":"Neuroscience letters","confidence":"High","confidence_rationale":"Tier 2 / Strong — native co-IP plus siRNA with functional transporter activity plus pulse-chase stability assay, multiple orthogonal methods","pmids":["20430067"],"is_preprint":false},{"year":2010,"finding":"NHERF2 expression restricts P2Y1R and mGluR5 coupling to CaV2.2 calcium channels in sympathetic neurons without affecting M-current inhibition; this selective restriction requires the NHERF2-binding motif on the receptors, demonstrating NHERF2 determines receptor-to-ion-channel coupling specificity.","method":"Intranuclear cDNA injection in sympathetic neurons, electrophysiology of M-current and N-type Ca²⁺ current, P2Y1R DTSL-motif deletion mutant","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — PDZ-binding motif deletion mutant plus electrophysiological functional assay in primary neurons, selectivity confirmed with non-binding receptor control","pmids":["20720114"],"is_preprint":false},{"year":2010,"finding":"NHERF2 and NHERF3 form the strongest heterodimerization among all NHERF family pairs; this heterodimerization requires NHERF2's PDZ domains and NHERF3's C-terminal PDZ recognition motif; the NHERF3-4A mutant defective in heterodimerization does not support carbachol-induced NHE3 inhibition.","method":"Pulldown, co-immunoprecipitation, FRET, FRAP, functional NHE3 inhibition assay with NHERF3-4A mutant","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (pulldown, co-IP, FRET, FRAP, functional assay with mutant), single lab","pmids":["24867958"],"is_preprint":false},{"year":2011,"finding":"NHERF2 is necessary for normal basal NHE3 activity and apical localization in mouse distal ileum; NHERF2-null ileum shows reduced brush border NHE3, and cAMP, cGMP, and Ca²⁺ (UTP) all fail to inhibit NHE3, while hyperosmolar inhibition is preserved; LPA stimulation of NHE3 is NHERF2-dependent.","method":"NHERF2-null mouse model, two-photon microscopy/SNARF-4F NHE3 activity assay, immunofluorescence","journal":"American journal of physiology. Cell physiology","confidence":"High","confidence_rationale":"Tier 2 / Strong — in vivo genetic knockout with quantitative two-photon microscopy NHE3 activity and localization measurements, multiple second messenger pathways tested","pmids":["21430287"],"is_preprint":false},{"year":2011,"finding":"Elevated intracellular Ca²⁺ acutely abolishes the NHERF2-NHE3 FRET signal within 1 min in opossum kidney cell microvilli, transiently increasing NHE3 mobility; the association is re-established by ~60 min; NHERF1-NHE3 association is not disrupted by elevated Ca²⁺.","method":"FRET (acceptor photobleaching), FRAP, co-immunoprecipitation in polarized OK cells","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — FRET plus FRAP plus co-IP, three orthogonal methods demonstrating dynamic Ca²⁺-dependent NHERF2-NHE3 dissociation","pmids":["21799002"],"is_preprint":false},{"year":2012,"finding":"CaMKII inhibits basal NHE3 activity by a NHERF2-dependent process; CaMKIIγ constitutively binds NHE3 between aa 586-605 in a Ca²⁺-dependent manner (less association when Ca²⁺ is elevated); CaMKII phosphorylates NHE3 under basal conditions at sites downstream of aa 690.","method":"CaMKII inhibitors (KN-93, KN-62), co-immunoprecipitation domain mapping, back phosphorylation assay, NHERF2 requirement established by cell model","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — phosphorylation assay plus domain mapping co-IP plus pharmacological inhibitors, multiple orthogonal methods in single study","pmids":["22371496"],"is_preprint":false},{"year":2012,"finding":"NHERF2 scaffolds a megalin-ClC-5 complex in proximal tubule cells; NHERF2 interacts with megalin via an internal NHERF binding domain in megalin's C-terminus and PDZ2 of NHERF2; siRNA silencing of NHERF2 abolishes the megalin-ClC-5 interaction without affecting megalin protein levels.","method":"GST pulldown, immunoprecipitation from rat kidney lysate, siRNA knockdown, fusion protein reconstitution","journal":"The international journal of biochemistry & cell biology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with fusion proteins plus native tissue co-IP plus siRNA, multiple orthogonal methods","pmids":["22349218"],"is_preprint":false},{"year":2013,"finding":"NHERF2 is more slowly mobile in brush border microvilli than NHERF1 or NHERF3; its slower mobility is determined by a unique C-terminal domain (including a non-conserved region plus ERM-binding domain); this C-terminal domain is also required for LPA stimulation of NHE3 activity/mobility and Ca²⁺ ionophore inhibition of NHE3.","method":"FRAP/confocal microscopy, chimeras and point mutants of NHERF1/2, functional NHE3 activity assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — FRAP with chimeric domain-swap mutants plus functional NHE3 assays, unique domain identified","pmids":["23612977"],"is_preprint":false},{"year":2013,"finding":"E3KARP (NHERF2) localizes to the base of microvilli (not along the full length like EBP50/NHERF1); this differential localization is determined by E3KARP's tail region; E3KARP exchanges more slowly from microvilli than EBP50, and this difference is also tail-determined.","method":"FRAP in live epithelial cells, chimeric tail constructs, proteomic pulldown","journal":"Molecular biology of the cell","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — FRAP plus chimeric construct analysis plus proteomic data, single lab","pmids":["23985317"],"is_preprint":false},{"year":2014,"finding":"LPA stimulation of NHE3 exocytosis requires NHERF2, and operates through an ERK-PLC-PKCδ signaling module that dynamically and reversibly releases NHE3 from NHERF2; PKCδ is necessary for LPA-stimulated NHE3 mobility and NHE3/NHERF2 dissociation.","method":"FRAP, co-immunoprecipitation, PKCδ knockdown, ERK and PLC inhibitors, NHE3 activity in OK cells","journal":"American journal of physiology. Cell physiology","confidence":"High","confidence_rationale":"Tier 2 / Strong — FRAP plus co-IP plus genetic knockdown plus pharmacological inhibitors, pathway ordering established","pmids":["24760985"],"is_preprint":false},{"year":2014,"finding":"NHERF2 interacts with estrogen receptor alpha (ERα) predominantly at the AF-1 domain and acts as a coactivator; overexpression of NHERF2 in MCF7 cells increases ERα transactivation, and NHERF2 together with SRC-1 synergistically enhances ERα activity at target gene promoters.","method":"Co-immunoprecipitation, ChIP at ERα target gene promoters, ERα transactivation reporter assays, stable overexpression in MCF7","journal":"Nucleic acids research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP plus ChIP plus functional reporter assay, single lab","pmids":["24771346"],"is_preprint":false},{"year":2014,"finding":"Crystal structure of NHERF2 PDZ1 domain in complex with LPA2 C-terminal peptide reveals that binding specificity is achieved through hydrogen bonds and hydrophobic contacts with the last four LPA2 residues; a small surface pocket adjacent to the ligand-binding site was identified.","method":"X-ray crystallography of PDZ1-LPA2 complex","journal":"Biochemical and biophysical research communications","confidence":"High","confidence_rationale":"Tier 1 / Moderate — crystal structure determination, single lab but direct structural evidence","pmids":["24613836"],"is_preprint":false},{"year":2015,"finding":"NHERF2 forms a complex with SCHIP1 and ezrin in podocyte foot processes; this complex is associated with cortical actin cytoskeleton dynamics in response to PDGF-BB signaling.","method":"Co-immunoprecipitation in cultured podocytes, immunofluorescence, zebrafish morpholino knockdown","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — co-IP in cultured cells plus in vivo zebrafish model, single lab","pmids":["25807495"],"is_preprint":false},{"year":2015,"finding":"NHERF2 contains an ERM-binding regulatory sequence (EBRS) located 19 residues upstream of the ERM-binding domain (EBD); EBRS facilitates NHERF2-ezrin interaction and is necessary for exclusive apical NHERF2 distribution in OK cells; phosphorylation of Ser303 in the EBRS decreases ezrin-binding affinity, dislocates NHERF2 to cytosol, increases NHERF2 mobility, and prevents dexamethasone stimulation of NHE3.","method":"EBRS deletion/point mutants, FRAP, co-immunoprecipitation with ezrin, phosphomimetic Ser303 mutants, NHE3 activity assays","journal":"The Biochemical journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — domain deletion plus phosphomimetic mutants plus FRAP plus functional NHE3 assay, multiple orthogonal methods","pmids":["26251448"],"is_preprint":false},{"year":2015,"finding":"E3KARP (NHERF2) exchange rate from microvilli is greatly enhanced during mitosis due to phosphorylation of Ser303 in its tail; A-Raf is required for Ser303 phosphorylation in mitotic cells; the S303D phosphomimetic mutation prevents E3KARP from substituting for EBP50 in microvillus formation.","method":"FRAP in mitotic cells, A-Raf RNAi, S303D phosphomimetic mutant, microvillus formation assay","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — FRAP plus genetic RNAi plus phosphomimetic mutant with functional microvillus assay, identifies kinase writer for Ser303","pmids":["26310448"],"is_preprint":false},{"year":2017,"finding":"Loss of NHERF1 and NHERF2 in human mast cells does not affect C3aR desensitization, internalization, ERK/Akt phosphorylation, or chemotaxis, but does inhibit C3a-induced degranulation, NF-κB activation, and chemokine production; C3aR does not associate with NHERF1 or NHERF2 despite having a PDZ motif.","method":"Lentiviral shRNA knockdown in human mast cells, functional degranulation, NF-κB and chemokine assays, co-immunoprecipitation (negative result for C3aR association)","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — stable shRNA knockdown with multiple functional readouts; negative C3aR-NHERF2 association is noteworthy","pmids":["23284683"],"is_preprint":false},{"year":2019,"finding":"HPV-16 and HPV-18 E6 oncoproteins interact with NHERF-2 via their PDZ-binding motifs and target NHERF-2 for proteasome-mediated degradation; E6-mediated NHERF-2 degradation leads to p27 downregulation and cyclin D1 upregulation, accelerating cell proliferation.","method":"Co-immunoprecipitation, proteasome inhibitor experiments, E6 PBM point mutants, NHERF-2 degradation assays in HPV-positive cervical tumor cells","journal":"Journal of virology","confidence":"High","confidence_rationale":"Tier 2 / Strong — co-IP plus mutagenesis plus proteasome inhibitor rescue plus functional proliferation assays in HPV-positive cancer cells","pmids":["31597772"],"is_preprint":false},{"year":2023,"finding":"NHERF2 stabilizes IκB protein by reducing its ubiquitination; SLC26A3 augments the NHERF2-IκB interaction, thereby inhibiting p65 nuclear translocation and NF-κB activity in colorectal cancer cells.","method":"Co-immunoprecipitation, ubiquitination assays, NF-κB reporter assays, p65 nuclear/cytoplasmic fractionation","journal":"Oncogenesis","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP plus ubiquitination assay plus functional NF-κB readout, single lab","pmids":["37573425"],"is_preprint":false},{"year":2024,"finding":"NHE3, NHERF2, and cGKII co-assemble in lipid raft microdomains of the small intestinal brush border membrane; NHERF2 is required for NHE3 raft association; Gucy2c activation decreases NHE3 raft association and shifts NHE3 from microvilli to terminal web in a cGKII- and NHERF2-dependent manner.","method":"Optiprep density gradient fractionation of Triton X-solubilized brush border membranes, NHERF2- and cGKII-knockout mice, confocal microscopy","journal":"Acta physiologica","confidence":"High","confidence_rationale":"Tier 2 / Strong — lipid raft fractionation plus multiple knockout mouse models (NHE3, cGKII, NHERF2) with localization readout","pmids":["38533975"],"is_preprint":false},{"year":2013,"finding":"NHERF2 is necessary for agonist-induced ERM phosphorylation in pulmonary artery endothelial cells; NHERF2 associates with all three ERM proteins and co-immunoprecipitates with Rho kinase 2 (ROCK2); NHERF2 depletion prevents ROCK2-ERM association; a NHERF2 mutant unable to bind ERM attenuates cell attachment.","method":"Co-immunoprecipitation, siRNA knockdown, NHERF2 ERM-binding mutant, ECIS cell attachment measurement, Matrigel tube formation","journal":"Cell communication and signaling","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP plus siRNA plus binding mutant plus functional assay, single lab","pmids":["24364877"],"is_preprint":false},{"year":2010,"finding":"NHERF2 is required for cGMP- and Ca²⁺-dependent but not cAMP-dependent inhibition of NHE3 in Caco-2/bbe cells; simultaneous knockdown of both NHERF1 and NHERF2 is required to abolish cAMP inhibition; EGF stimulation of NHE3 is NHERF1-dependent (not NHERF2-dependent).","method":"Lentivirus shRNA stable knockdown and adenovirus siRNA transient knockdown in Caco-2/bbe cells, NHE3 activity assays","journal":"American journal of physiology. Cell physiology","confidence":"High","confidence_rationale":"Tier 2 / Strong — dual stable and transient knockdown approaches, multiple second messenger pathways tested, single lab with rigorous controls","pmids":["21191106"],"is_preprint":false},{"year":2017,"finding":"NHERF2 and NHERF3 have overlapping requirements in mouse jejunum for NHE3 regulation by LPA (stimulation) and by elevated Ca²⁺ and cGMP (inhibition); glucose-stimulated NHE3 activity is reduced in NHERF2- but not NHERF3-null mice.","method":"NHERF2 and NHERF3 knockout mice, two-photon microscopy/SNARF-4F NHE3 activity","journal":"American journal of physiology. Gastrointestinal and liver physiology","confidence":"High","confidence_rationale":"Tier 2 / Strong — two independent genetic knockouts with quantitative in vivo NHE3 activity, confirms prior findings in different intestinal segment","pmids":["28882822"],"is_preprint":false}],"current_model":"NHERF2 is a dual-PDZ-domain scaffold protein that functions primarily as an apical membrane organizer in epithelial cells, assembling macromolecular signaling complexes by binding NHE3 (via PDZ2), CFTR, LPA receptors (LPA2/LPA5), P2Y1R, mGluR5, and other transporters/receptors through PDZ domain interactions while connecting them to the actin cytoskeleton via an ERM-binding domain that engages ezrin; it serves as a platform for cAMP (PKA), cGMP (cGKII anchoring), and Ca²⁺/PKCα/CaMKII second messenger inhibition of NHE3, for SGK1-mediated stimulation of NHE3 and other transporters (ROMK1, PEPT2, TRPV5), and for LPA5-mediated stimulation of NHE3 via PLC-ERK-PKCδ signaling, with its function dynamically regulated by phosphorylation of Ser303 (by A-Raf during mitosis) in its unique C-terminal region, which decreases ezrin binding and increases microvillar mobility."},"narrative":{"mechanistic_narrative":"NHERF2 (E3KARP) is a dual-PDZ-domain apical scaffold that organizes macromolecular signaling complexes in polarized epithelia, coupling membrane transporters and receptors to regulatory kinases and to the actin cytoskeleton [PMID:9748260, PMID:9792717, PMID:21430287]. Its second PDZ domain binds the C-terminal PDZ motifs of the Na+/H+ exchanger NHE3, CFTR, the Cl-/HCO3- exchanger DRA, the LPA2 receptor, P2Y1R, mGluR5, and other transporters with high affinity, while a C-terminal ERM-binding domain engages ezrin to tether these complexes near the apical actin cortex [PMID:9748260, PMID:9792717, PMID:10893422, PMID:12369822, PMID:15143197, PMID:15901899, PMID:24613836]. Through this platform NHERF2 specifically (and distinctly from NHERF1) localizes second-messenger machinery to NHE3: it anchors PKA-, cGMP-dependent protein kinase II (cGKII), Ca2+/PKCalpha, and CaMKII signaling for NHE3 inhibition, and SGK1 for stimulation of NHE3 and other transporters including ROMK1, PEPT2, and TRPV5 [PMID:9748260, PMID:9792717, PMID:11751930, PMID:12954600, PMID:15722341, PMID:22371496, PMID:15665527, PMID:19088452, PMID:12444200]. NHERF2 also controls receptor output by determining G-protein coupling and effector specificity, linking LPA2 to PLCbeta3/ERK/COX-2 signaling and restricting P2Y1R/mGluR5 coupling to CaV2.2 channels [PMID:15143197, PMID:21134377, PMID:20720114]. Knockout mouse studies establish that NHERF2 is required in intestine for basal NHE3 apical localization and for cGMP-, Ca2+-, and LPA-mediated regulation of NHE3 and CFTR-dependent secretion, tethering NHE3 near the terminal web and within brush-border lipid rafts [PMID:19221439, PMID:19800338, PMID:20962002, PMID:21430287, PMID:38533975]. The interaction is dynamic: elevated Ca2+ or LPA stimulation (via an ERK-PLC-PKCdelta module) transiently dissociates the NHERF2-NHE3 complex to increase exchanger mobility, and phosphorylation of Ser303 in NHERF2's unique C-terminal ERM-binding regulatory sequence by A-Raf during mitosis reduces ezrin binding and releases NHERF2 into the cytosol [PMID:21799002, PMID:24760985, PMID:26251448, PMID:26310448]. Beyond epithelial transport, NHERF2 acts as a negative regulator of endothelial proliferation and is targeted for degradation by HPV E6 oncoproteins, linking its loss to p27/cyclin D1 dysregulation [PMID:22343917, PMID:31597772].","teleology":[{"year":1998,"claim":"Established the founding scaffold model: how cAMP-dependent regulation of NHE3 is spatially organized, by showing NHERF2 physically links NHE3 to ezrin and PKA.","evidence":"In vitro binding with domain mapping and co-IP in fibroblasts/opossum kidney cells, with NHE3 activity assays","pmids":["9748260","9792717"],"confidence":"High","gaps":["Did not establish whether NHERF2 vs NHERF1 confer distinct selectivity","Direct demonstration of PKA tethering in native epithelium absent"]},{"year":1998,"claim":"Defined NHERF2 as a passive adapter rather than a kinase substrate, clarifying that its regulatory role is structural localization of PKA.","evidence":"In vivo phosphorylation studies and co-IP in opossum kidney cells","pmids":["9792717"],"confidence":"Medium","gaps":["Did not exclude regulatory phosphorylation by other kinases (later shown at Ser303)"]},{"year":2000,"claim":"Extended the scaffold to CFTR, showing NHERF2 functionally potentiates cAMP-stimulated Cl- currents via PDZ2 and ezrin.","evidence":"Nanomolar binding assays, co-IP, and Xenopus oocyte electrophysiology","pmids":["10893422"],"confidence":"High","gaps":["Physiological context of CFTR regulation not yet tested in epithelium"]},{"year":2001,"claim":"Identified NHERF2 as the specific scaffold (vs NHERF1) coupling the kinase SGK1 to NHE3, explaining glucocorticoid activation of the exchanger.","evidence":"Co-expression with dominant-negative kinase-dead SGK1 and NHE3 activity assays in two cell lines","pmids":["11751930"],"confidence":"High","gaps":["Direct SGK1 phosphorylation site on NHE3 or NHERF2 not mapped here"]},{"year":2001,"claim":"Showed NHERF2 self- and hetero-oligomerizes via PDZ domains, indicating scaffolds can multimerize to assemble larger complexes.","evidence":"Purified PDZ domain association assays and co-IP with tagged constructs","pmids":["11456497"],"confidence":"Medium","gaps":["Functional consequence of oligomerization on transporter regulation not established","Stoichiometry in vivo unknown"]},{"year":2002,"claim":"Resolved the mechanism of Ca2+-dependent NHE3 inhibition: NHERF2 specifically recruits alpha-actinin-4 and PKCalpha to drive NHE3 oligomerization and endocytosis.","evidence":"Stable transfection, NHE3 activity, co-IP, dominant-negative, and surface biotinylation in PS120 cells","pmids":["11948184","12954600"],"confidence":"High","gaps":["Whether oligomerization precedes or follows endocytosis not fully ordered","alpha-actinin-4 recruitment trigger details incomplete"]},{"year":2002,"claim":"Broadened the apical interactome to include the DRA Cl-/HCO3- exchanger and adenosine A2b receptor, supporting NHERF2 as a coordinator of parallel transport/receptor systems.","evidence":"In vitro PDZ binding with GST fusions and agonist-dependent co-IP in intestinal epithelial cell lines","pmids":["12369822","12080047"],"confidence":"Medium","gaps":["Functional coupling of DRA and NHE3 via NHERF2 not demonstrated physiologically","A2bR interaction context limited to co-IP"]},{"year":2004,"claim":"Demonstrated NHERF2 dictates receptor signaling output by linking LPA2 to PLCbeta3, forming a ternary complex driving ERK/COX-2 signaling.","evidence":"Co-IP, PDZ mutants, siRNA knockdown, and inositol phosphate assays with isoform selectivity","pmids":["15143197","15238220"],"confidence":"High","gaps":["In vivo relevance not yet established (addressed later by knockouts)"]},{"year":2005,"claim":"Established NHERF2 as a protein kinase G anchoring protein, identifying it as required for cGMP (cGKII)-mediated NHE3 inhibition distinct from NHERF1.","evidence":"Co-expression, in vitro cGKII binding, non-myristoylated mutant, and NHE3 activity assays","pmids":["15722341"],"confidence":"High","gaps":["Structural basis of cGKII recognition not resolved"]},{"year":2005,"claim":"Generalized the receptor-tethering function to neuronal/glial GPCRs (P2Y1R, mGluR5) and to apical polarity (podocalyxin), prolonging Ca2+ signaling and shaping epithelial organization.","evidence":"PDZ array screens, co-IP, point-mutant functional Ca2+ assays, and RNAi polarization phenotypes","pmids":["15901899","16891310","15642748"],"confidence":"High","gaps":["Mechanism by which NHERF2 prolongs Ca2+ signals (effector retention vs recycling) not fully resolved"]},{"year":2008,"claim":"Expanded the SGK1/NHERF2 module to multiple transporters (ROMK1, TRPV5, PEPT2), showing NHERF2 stabilizes surface abundance by limiting endocytosis.","evidence":"Xenopus oocyte electrophysiology, surface abundance assays, and dynasore endocytosis block","pmids":["12444200","15665527","19088452"],"confidence":"Medium","gaps":["Native-tissue relevance for these transporters not demonstrated","Direct SGK1 phosphosites variably mapped"]},{"year":2009,"claim":"Provided in vivo genetic proof that NHERF2 couples LPA receptors (LPA5, not LPA2) to NHE3 stimulation and to inhibitory LPA-CFTR signaling in intestine.","evidence":"Nherf2-/- and Lpa2-/- mice with duodenal HCO3- secretion and intestinal fluid absorption measurements","pmids":["19221439","19800338"],"confidence":"High","gaps":["Reconciliation of LPA2 (in vitro) vs LPA5 (in vivo) receptor usage incompletely resolved"]},{"year":2010,"claim":"Showed NHERF2 determines LPA2 G-protein coupling specificity by competing with MAGI-3, controlling migration vs NF-kappaB outcomes.","evidence":"Competitive binding, co-IP, and migration/invasion/IP/NF-kappaB assays in colorectal cells","pmids":["21134377"],"confidence":"High","gaps":["Quantitative stoichiometry of the NHERF2/MAGI-3 competition in vivo unknown"]},{"year":2010,"claim":"Revealed the NHERF2-NHE3 interaction is dynamic, with LPA and Ca2+ transiently dissociating the complex to mobilize NHE3 via PI3K-dependent exocytosis.","evidence":"FRAP, acceptor-photobleaching FRET, co-IP, and PI3K inhibitor experiments in OK cells","pmids":["20571054","21799002"],"confidence":"High","gaps":["Molecular trigger for reassociation at 60 min not identified"]},{"year":2010,"claim":"Established NHERF2 as the ezrin-dependent apical anchor for additional targets (PMCA2w/b, GLAST, TRPC4) and as a determinant of receptor-to-channel coupling in neurons.","evidence":"Surface biotinylation, FRAP, actin disruption, pulse-chase stability, native co-IP, and neuronal electrophysiology","pmids":["20663896","20430067","15590898","20720114"],"confidence":"High","gaps":["Whether ezrin tethering is required for all of these targets uniformly not established"]},{"year":2010,"claim":"Identified NHERF2 as a negative regulator of endothelial proliferation, linking its loss to elevated Ca2+, c-Myc/cyclin D1, and reduced p27.","evidence":"siRNA knockdown, proliferation/cell-cycle analysis, and mouse hemangioma model","pmids":["22343917"],"confidence":"Medium","gaps":["Mechanism connecting scaffold loss to cell-cycle gene changes not fully defined"]},{"year":2011,"claim":"Genetically confirmed NHERF2 is essential for basal NHE3 apical localization and for cAMP/cGMP/Ca2+ regulation across intestinal segments, with selective preservation of hyperosmolar inhibition.","evidence":"NHERF2-null mice with two-photon microscopy NHE3 activity and immunofluorescence","pmids":["21430287","20962002"],"confidence":"High","gaps":["Redundancy with NHERF3 not yet dissected here"]},{"year":2012,"claim":"Added CaMKII and megalin-ClC-5 to the NHERF2-organized network, showing roles in basal NHE3 inhibition and proximal tubule receptor complex assembly.","evidence":"Phosphorylation/back-phosphorylation assays, domain-mapping co-IP, GST pulldown, and siRNA in tissue/cell models","pmids":["22371496","22349218"],"confidence":"High","gaps":["CaMKII NHE3 phosphosite location only partially mapped","Functional output of megalin-ClC-5 scaffolding in vivo not measured"]},{"year":2013,"claim":"Localized NHERF2's distinctive slow microvillar mobility and base-of-microvillus positioning to its unique C-terminal tail, which is required for LPA stimulation and Ca2+ inhibition of NHE3.","evidence":"FRAP with NHERF1/2 chimeras and point mutants, functional NHE3 assays","pmids":["23612977","23985317"],"confidence":"High","gaps":["Molecular partners conferring slow exchange not all identified"]},{"year":2013,"claim":"Linked NHERF2 to ERM/ROCK2 signaling in endothelium, establishing a role in agonist-induced ERM phosphorylation and cell attachment.","evidence":"Co-IP, siRNA, ERM-binding mutant, and ECIS/Matrigel functional assays","pmids":["24364877"],"confidence":"Medium","gaps":["Direct ROCK2-NHERF2 binding interface not mapped"]},{"year":2014,"claim":"Defined the LPA-stimulated NHE3 mobilization pathway as an ERK-PLC-PKCdelta module that reversibly releases NHE3 from NHERF2, and identified a nuclear coactivator role for NHERF2 with ERalpha.","evidence":"FRAP, co-IP, PKCdelta knockdown, inhibitor ordering in OK cells; co-IP/ChIP/reporter assays in MCF7","pmids":["24760985","24771346","24613836"],"confidence":"High","gaps":["How a predominantly apical scaffold accesses the nucleus for ERalpha coactivation not reconciled"]},{"year":2015,"claim":"Identified the Ser303-containing ERM-binding regulatory sequence (EBRS) as the master switch: its phosphorylation by A-Raf during mitosis reduces ezrin binding, relocates NHERF2 to cytosol, and disables SGK1/dexamethasone stimulation of NHE3.","evidence":"EBRS/phosphomimetic mutants, FRAP, ezrin co-IP, A-Raf RNAi, and NHE3/microvillus functional assays","pmids":["26251448","26310448"],"confidence":"High","gaps":["Phosphatase reversing Ser303 not identified","Signals controlling A-Raf activity toward NHERF2 outside mitosis unknown"]},{"year":2017,"claim":"Defined functional redundancy and division of labor between NHERF2 and NHERF3 in intestinal NHE3 regulation, with NHERF2 uniquely required for glucose-stimulated activity.","evidence":"NHERF2 and NHERF3 knockout mice with two-photon NHE3 activity; mast cell shRNA functional assays","pmids":["28882822","24867958","23284683"],"confidence":"High","gaps":["Mechanistic basis of NHERF2-specific glucose response not defined","C3aR functional effects occur without direct NHERF2 association"]},{"year":2019,"claim":"Connected NHERF2 loss to oncogenesis, showing HPV E6 targets it for proteasomal degradation to deregulate p27/cyclin D1, and later that NHERF2 stabilizes IkappaB to restrain NF-kappaB.","evidence":"Co-IP, E6 PBM mutants, proteasome inhibitor rescue, ubiquitination and NF-kappaB reporter assays in cancer cells","pmids":["31597772","37573425"],"confidence":"High","gaps":["NHERF2-IkappaB stabilization confirmed in a single study/system","Whether E6-driven degradation operates in primary tumors not established"]},{"year":2024,"claim":"Placed the NHE3-NHERF2-cGKII complex in brush-border lipid rafts and showed NHERF2 is required for NHE3 raft association and guanylyl-cyclase-C-triggered redistribution.","evidence":"Density-gradient raft fractionation with NHE3, cGKII, and NHERF2 knockout mice and confocal imaging","pmids":["38533975"],"confidence":"High","gaps":["Lipid determinants recruiting NHERF2 to rafts not identified"]},{"year":null,"claim":"How NHERF2's apical transport-scaffolding function mechanistically relates to its nuclear (ERalpha, SRY) and tumor-suppressive (IkappaB, p27) roles, and what governs target selection among its many PDZ ligands in a single cell, remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unified model linking membrane scaffold vs nuclear functions","Determinants of competitive ligand selection among co-expressed PDZ partners unknown","Structural basis for PDZ2 promiscuity vs PDZ1 selectivity only partially defined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,2,3,13,30]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[5,10,24,29,33]},{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[0,27,47]},{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[38]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,2,26,27,46]},{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[0,27,35,36,41]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[41]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[17,38]}],"pathway":[{"term_id":"R-HSA-382551","term_label":"Transport of small molecules","supporting_discovery_ids":[0,5,13,26,31]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[10,14,18,24,29]},{"term_id":"R-HSA-9609507","term_label":"Protein localization","supporting_discovery_ids":[20,27,16,36]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[44,45]}],"complexes":["NHE3-NHERF2-ezrin scaffold","LPA2-NHERF2-PLCbeta3 ternary complex","megalin-NHERF2-ClC-5 complex","NHERF2-SCHIP1-ezrin complex"],"partners":["NHE3","EZR","CFTR","SGK1","LPAR2","PRKG2","P2RY1","GRM5"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q15599","full_name":"Na(+)/H(+) exchange regulatory cofactor NHE-RF2","aliases":["NHE3 kinase A regulatory protein E3KARP","SRY-interacting protein 1","SIP-1","Sodium-hydrogen exchanger regulatory factor 2","Solute carrier family 9 isoform A3 regulatory factor 2","Tyrosine kinase activator protein 1","TKA-1"],"length_aa":337,"mass_kda":37.4,"function":"Scaffold protein that connects plasma membrane proteins with members of the ezrin/moesin/radixin family and thereby helps to link them to the actin cytoskeleton and to regulate their surface expression. Necessary for cAMP-mediated phosphorylation and inhibition of SLC9A3 (PubMed:18829453). May also act as scaffold protein in the nucleus","subcellular_location":"Endomembrane system; Nucleus; Apical cell membrane","url":"https://www.uniprot.org/uniprotkb/Q15599/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/NHERF2","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":true,"resolved_as":"SLC9A3R2","ensg_id":"ENSG00000065054","cell_line_id":"CID001376","localizations":[{"compartment":"vesicles","grade":3},{"compartment":"golgi","grade":2}],"interactors":[{"gene":"PODXL","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID001376","total_profiled":1310},"omim":[{"mim_id":"619206","title":"SCHWANNOMIN-INTERACTING PROTEIN 1; SCHIP1","url":"https://www.omim.org/entry/619206"},{"mim_id":"607392","title":"WW DOMAIN-CONTAINING TRANSCRIPTION REGULATOR 1; WWTR1","url":"https://www.omim.org/entry/607392"},{"mim_id":"606553","title":"SOLUTE CARRIER FAMILY 9, MEMBER 3, REGULATOR 2; SLC9A3R2","url":"https://www.omim.org/entry/606553"},{"mim_id":"604990","title":"SOLUTE CARRIER FAMILY 9, MEMBER 3, REGULATOR 1; SLC9A3R1","url":"https://www.omim.org/entry/604990"},{"mim_id":"602632","title":"PODOCALYXIN-LIKE; PODXL","url":"https://www.omim.org/entry/602632"}],"hpa":{"profiled":true,"resolved_as":"SLC9A3R2","reliability":"Supported","locations":[{"location":"Plasma membrane","reliability":"Supported"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"heart muscle","ntpm":571.9}],"url":"https://www.proteinatlas.org/search/SLC9A3R2"},"hgnc":{"alias_symbol":["SIP-1","TKA-1","NHERF-2","E3KARP","OCTS2"],"prev_symbol":["SLC9A3R2"]},"alphafold":{"accession":"Q15599","domains":[{"cath_id":"2.30.42.10","chopping":"10-111","consensus_level":"high","plddt":81.032,"start":10,"end":111},{"cath_id":"2.30.42.10","chopping":"151-250","consensus_level":"high","plddt":85.2657,"start":151,"end":250}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q15599","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q15599-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q15599-F1-predicted_aligned_error_v6.png","plddt_mean":68.81},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=NHERF2","jax_strain_url":"https://www.jax.org/strain/search?query=NHERF2"},"sequence":{"accession":"Q15599","fasta_url":"https://rest.uniprot.org/uniprotkb/Q15599.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q15599/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q15599"}},"corpus_meta":[{"pmid":"19221439","id":"PMC_19221439","title":"Differential roles of NHERF1, NHERF2, and PDZK1 in regulating CFTR-mediated intestinal anion secretion in mice.","date":"2009","source":"The Journal of clinical investigation","url":"https://pubmed.ncbi.nlm.nih.gov/19221439","citation_count":303,"is_preprint":false},{"pmid":"9748260","id":"PMC_9748260","title":"NHE3 kinase A regulatory protein E3KARP binds the epithelial brush border Na+/H+ exchanger NHE3 and the cytoskeletal protein ezrin.","date":"1998","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/9748260","citation_count":244,"is_preprint":false},{"pmid":"9792717","id":"PMC_9792717","title":"The role of NHERF and E3KARP in the cAMP-mediated inhibition of NHE3.","date":"1998","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/9792717","citation_count":178,"is_preprint":false},{"pmid":"10893422","id":"PMC_10893422","title":"E3KARP mediates the association of ezrin and protein kinase A with the cystic fibrosis transmembrane conductance regulator in airway cells.","date":"2000","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/10893422","citation_count":176,"is_preprint":false},{"pmid":"15642748","id":"PMC_15642748","title":"Gp135/podocalyxin and NHERF-2 participate in the formation of a preapical domain during polarization of MDCK cells.","date":"2005","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/15642748","citation_count":165,"is_preprint":false},{"pmid":"11751930","id":"PMC_11751930","title":"Glucocorticoid activation of Na(+)/H(+) exchanger isoform 3 revisited. The roles of SGK1 and NHERF2.","date":"2001","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11751930","citation_count":153,"is_preprint":false},{"pmid":"11948184","id":"PMC_11948184","title":"Ca(2+)-dependent inhibition of Na+/H+ exchanger 3 (NHE3) requires an NHE3-E3KARP-alpha-actinin-4 complex for oligomerization and endocytosis.","date":"2002","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11948184","citation_count":106,"is_preprint":false},{"pmid":"12444200","id":"PMC_12444200","title":"The serum and glucocorticoid-inducible kinase SGK1 and the Na+/H+ exchange regulating factor NHERF2 synergize to stimulate the renal outer medullary K+ channel ROMK1.","date":"2002","source":"Journal of the American Society of Nephrology : JASN","url":"https://pubmed.ncbi.nlm.nih.gov/12444200","citation_count":105,"is_preprint":false},{"pmid":"11456497","id":"PMC_11456497","title":"Oligomerization of NHERF-1 and NHERF-2 PDZ domains: differential regulation by association with receptor carboxyl-termini and by phosphorylation.","date":"2001","source":"Biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11456497","citation_count":100,"is_preprint":false},{"pmid":"19800338","id":"PMC_19800338","title":"Lysophosphatidic acid stimulates the intestinal brush border Na(+)/H(+) exchanger 3 and fluid absorption via LPA(5) and NHERF2.","date":"2009","source":"Gastroenterology","url":"https://pubmed.ncbi.nlm.nih.gov/19800338","citation_count":95,"is_preprint":false},{"pmid":"11106646","id":"PMC_11106646","title":"Hierarchy of merlin and ezrin N- and C-terminal domain interactions in homo- and heterotypic associations and their relationship to binding of scaffolding proteins EBP50 and E3KARP.","date":"2000","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11106646","citation_count":85,"is_preprint":false},{"pmid":"12080047","id":"PMC_12080047","title":"The adenosine 2b receptor is recruited to the plasma membrane and associates with E3KARP and Ezrin upon agonist stimulation.","date":"2002","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/12080047","citation_count":82,"is_preprint":false},{"pmid":"12954600","id":"PMC_12954600","title":"Ca2+-dependent inhibition of NHE3 requires PKC alpha which binds to E3KARP to decrease surface NHE3 containing plasma membrane complexes.","date":"2003","source":"American journal of physiology. Cell physiology","url":"https://pubmed.ncbi.nlm.nih.gov/12954600","citation_count":82,"is_preprint":false},{"pmid":"15722341","id":"PMC_15722341","title":"cGMP inhibition of Na+/H+ antiporter 3 (NHE3) requires PDZ domain adapter NHERF2, a broad specificity protein kinase G-anchoring protein.","date":"2005","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/15722341","citation_count":80,"is_preprint":false},{"pmid":"15901899","id":"PMC_15901899","title":"P2Y1 receptor signaling is controlled by interaction with the PDZ scaffold NHERF-2.","date":"2005","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/15901899","citation_count":79,"is_preprint":false},{"pmid":"12369822","id":"PMC_12369822","title":"The down regulated in adenoma (dra) gene product binds to the second PDZ domain of the NHE3 kinase A regulatory protein (E3KARP), potentially linking intestinal Cl-/HCO3- exchange to Na+/H+ exchange.","date":"2002","source":"Biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/12369822","citation_count":77,"is_preprint":false},{"pmid":"15143197","id":"PMC_15143197","title":"NHERF2 specifically interacts with LPA2 receptor and defines the specificity and efficiency of receptor-mediated phospholipase C-beta3 activation.","date":"2004","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/15143197","citation_count":76,"is_preprint":false},{"pmid":"11893083","id":"PMC_11893083","title":"Distinct cell type-specific expression of scaffolding proteins EBP50 and E3KARP: EBP50 is generally expressed with ezrin in specific epithelia, whereas E3KARP is not.","date":"2002","source":"European journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/11893083","citation_count":68,"is_preprint":false},{"pmid":"15319523","id":"PMC_15319523","title":"Regulation of the epithelial Ca2+ channel TRPV5 by the NHE regulating factor NHERF2 and the serum and glucocorticoid inducible kinase isoforms SGK1 and SGK3 expressed in Xenopus oocytes.","date":"2004","source":"Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/15319523","citation_count":67,"is_preprint":false},{"pmid":"11285285","id":"PMC_11285285","title":"Identification of EPI64, a TBC/rabGAP domain-containing microvillar protein that binds to the first PDZ domain of EBP50 and E3KARP.","date":"2001","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/11285285","citation_count":66,"is_preprint":false},{"pmid":"15665527","id":"PMC_15665527","title":"Requirement of PDZ domains for the stimulation of the epithelial Ca2+ channel TRPV5 by the NHE regulating factor NHERF2 and the serum and glucocorticoid inducible kinase SGK1.","date":"2005","source":"Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/15665527","citation_count":57,"is_preprint":false},{"pmid":"12649600","id":"PMC_12649600","title":"Concerted roles of SGK1 and the Na+/H+ exchanger regulatory factor 2 (NHERF2) in regulation of NHE3.","date":"2003","source":"Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/12649600","citation_count":56,"is_preprint":false},{"pmid":"19088452","id":"PMC_19088452","title":"The peptide transporter PEPT2 is targeted by the protein kinase SGK1 and the scaffold protein NHERF2.","date":"2008","source":"Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/19088452","citation_count":55,"is_preprint":false},{"pmid":"21134377","id":"PMC_21134377","title":"MAGI-3 competes with NHERF-2 to negatively regulate LPA2 receptor signaling in colon cancer cells.","date":"2010","source":"Gastroenterology","url":"https://pubmed.ncbi.nlm.nih.gov/21134377","citation_count":53,"is_preprint":false},{"pmid":"16891310","id":"PMC_16891310","title":"The PDZ scaffold NHERF-2 interacts with mGluR5 and regulates receptor activity.","date":"2006","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/16891310","citation_count":50,"is_preprint":false},{"pmid":"21191106","id":"PMC_21191106","title":"NHERF1 and NHERF2 are necessary for multiple but usually separate aspects of basal and acute regulation of NHE3 activity.","date":"2010","source":"American journal of physiology. Cell physiology","url":"https://pubmed.ncbi.nlm.nih.gov/21191106","citation_count":49,"is_preprint":false},{"pmid":"9831664","id":"PMC_9831664","title":"Genomic structure and sequence of a human homologue (NTHL1/NTH1) of Escherichia coli endonuclease III with those of the adjacent parts of TSC2 and SLC9A3R2 genes.","date":"1998","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/9831664","citation_count":40,"is_preprint":false},{"pmid":"21430287","id":"PMC_21430287","title":"NHERF2 is necessary for basal activity, second messenger inhibition, and LPA stimulation of NHE3 in mouse distal ileum.","date":"2011","source":"American journal of physiology. Cell physiology","url":"https://pubmed.ncbi.nlm.nih.gov/21430287","citation_count":38,"is_preprint":false},{"pmid":"20618342","id":"PMC_20618342","title":"Binding to Na(+) /H(+) exchanger regulatory factor 2 (NHERF2) affects trafficking and function of the enteropathogenic Escherichia coli type III secretion system effectors Map, EspI and NleH.","date":"2010","source":"Cellular microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/20618342","citation_count":38,"is_preprint":false},{"pmid":"20962002","id":"PMC_20962002","title":"Loss of PDZ-adaptor protein NHERF2 affects membrane localization and cGMP- and [Ca2+]- but not cAMP-dependent regulation of Na+/H+ exchanger 3 in murine intestine.","date":"2010","source":"The Journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/20962002","citation_count":33,"is_preprint":false},{"pmid":"16166090","id":"PMC_16166090","title":"NHERF2/SIP-1 interacts with mouse SRY via a different mechanism than human SRY.","date":"2005","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/16166090","citation_count":31,"is_preprint":false},{"pmid":"15590898","id":"PMC_15590898","title":"Expression of TRPC4 channel protein that interacts with NHERF-2 in rat descending vasa recta.","date":"2004","source":"American journal of physiology. Cell physiology","url":"https://pubmed.ncbi.nlm.nih.gov/15590898","citation_count":29,"is_preprint":false},{"pmid":"20663896","id":"PMC_20663896","title":"Apical scaffolding protein NHERF2 modulates the localization of alternatively spliced plasma membrane Ca2+ pump 2B variants in polarized epithelial cells.","date":"2010","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/20663896","citation_count":26,"is_preprint":false},{"pmid":"22349218","id":"PMC_22349218","title":"The interaction between megalin and ClC-5 is scaffolded by the Na⁺-H⁺ exchanger regulatory factor 2 (NHERF2) in proximal tubule cells.","date":"2012","source":"The international journal of biochemistry & cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/22349218","citation_count":25,"is_preprint":false},{"pmid":"20571054","id":"PMC_20571054","title":"NHE3 mobility in brush borders increases upon NHERF2-dependent stimulation by lyophosphatidic acid.","date":"2010","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/20571054","citation_count":21,"is_preprint":false},{"pmid":"12865627","id":"PMC_12865627","title":"Expression of NHERF-1, NHERF-2, PDGFR-alpha, and PDGFR-beta in normal human kidneys and in renal transplant rejection.","date":"2002","source":"Pathobiology : journal of immunopathology, molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/12865627","citation_count":20,"is_preprint":false},{"pmid":"7681542","id":"PMC_7681542","title":"Sequence analysis of tka(-)-1 and tkb(+)-1 alleles in L5178Y tk+/- mouse-lymphoma cells and spontaneous tk-/- mutants.","date":"1993","source":"Mutation research","url":"https://pubmed.ncbi.nlm.nih.gov/7681542","citation_count":20,"is_preprint":false},{"pmid":"22343917","id":"PMC_22343917","title":"NHERF-2 maintains endothelial homeostasis.","date":"2012","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/22343917","citation_count":18,"is_preprint":false},{"pmid":"18256311","id":"PMC_18256311","title":"Urine electrolyte, mineral, and protein excretion in NHERF-2 and NHERF-1 null mice.","date":"2008","source":"American journal of physiology. Renal physiology","url":"https://pubmed.ncbi.nlm.nih.gov/18256311","citation_count":18,"is_preprint":false},{"pmid":"35674015","id":"PMC_35674015","title":"Intestinal Gastrin/CCKBR (Cholecystokinin B Receptor) Ameliorates Salt-Sensitive Hypertension by Inhibiting Intestinal Na+/H+ Exchanger 3 Activity Through a PKC (Protein Kinase C)-Mediated NHERF1 and NHERF2 Pathway.","date":"2022","source":"Hypertension (Dallas, Tex. : 1979)","url":"https://pubmed.ncbi.nlm.nih.gov/35674015","citation_count":18,"is_preprint":false},{"pmid":"16824484","id":"PMC_16824484","title":"NHE3 inhibits PKA-dependent functional expression of CFTR by NHERF2 PDZ interactions.","date":"2006","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/16824484","citation_count":18,"is_preprint":false},{"pmid":"15238220","id":"PMC_15238220","title":"Lysophosphatidic acid induces exocytic trafficking of Na(+)/H(+) exchanger 3 by E3KARP-dependent activation of phospholipase C.","date":"2004","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/15238220","citation_count":18,"is_preprint":false},{"pmid":"23985317","id":"PMC_23985317","title":"The tails of apical scaffolding proteins EBP50 and E3KARP regulate their localization and dynamics.","date":"2013","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/23985317","citation_count":17,"is_preprint":false},{"pmid":"21799002","id":"PMC_21799002","title":"Elevated calcium acutely regulates dynamic interactions of NHERF2 and NHE3 proteins in opossum kidney (OK) cell microvilli.","date":"2011","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/21799002","citation_count":17,"is_preprint":false},{"pmid":"24867958","id":"PMC_24867958","title":"NHERF2/NHERF3 protein heterodimerization and macrocomplex formation are required for the inhibition of NHE3 activity by carbachol.","date":"2014","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/24867958","citation_count":16,"is_preprint":false},{"pmid":"23612977","id":"PMC_23612977","title":"NHERF2 protein mobility rate is determined by a unique C-terminal domain that is also necessary for its regulation of NHE3 protein in OK cells.","date":"2013","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/23612977","citation_count":16,"is_preprint":false},{"pmid":"25807495","id":"PMC_25807495","title":"Schip1 is a novel podocyte foot process protein that mediates actin cytoskeleton rearrangements and forms a complex with Nherf2 and ezrin.","date":"2015","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/25807495","citation_count":16,"is_preprint":false},{"pmid":"24771346","id":"PMC_24771346","title":"SIP1/NHERF2 enhances estrogen receptor alpha transactivation in breast cancer cells.","date":"2014","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/24771346","citation_count":15,"is_preprint":false},{"pmid":"31597772","id":"PMC_31597772","title":"PDZ Domain-Containing Protein NHERF-2 Is a Novel Target of Human Papillomavirus 16 (HPV-16) and HPV-18.","date":"2019","source":"Journal of virology","url":"https://pubmed.ncbi.nlm.nih.gov/31597772","citation_count":15,"is_preprint":false},{"pmid":"22371496","id":"PMC_22371496","title":"Calmodulin kinase II constitutively binds, phosphorylates, and inhibits brush border Na+/H+ exchanger 3 (NHE3) by a NHERF2 protein-dependent process.","date":"2012","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/22371496","citation_count":15,"is_preprint":false},{"pmid":"24760985","id":"PMC_24760985","title":"Lysophosphatidic acid stimulation of NHE3 exocytosis in polarized epithelial cells occurs with release from NHERF2 via ERK-PLC-PKCδ signaling.","date":"2014","source":"American journal of physiology. Cell physiology","url":"https://pubmed.ncbi.nlm.nih.gov/24760985","citation_count":15,"is_preprint":false},{"pmid":"15115658","id":"PMC_15115658","title":"NHERF2 increases platelet-derived growth factor-induced proliferation through PI-3-kinase/Akt-, ERK-, and Src family kinase-dependent pathway.","date":"2004","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/15115658","citation_count":13,"is_preprint":false},{"pmid":"28882822","id":"PMC_28882822","title":"Both NHERF3 and NHERF2 are necessary for multiple aspects of acute regulation of NHE3 by elevated Ca2+, cGMP, and lysophosphatidic acid.","date":"2017","source":"American journal of physiology. Gastrointestinal and liver physiology","url":"https://pubmed.ncbi.nlm.nih.gov/28882822","citation_count":13,"is_preprint":false},{"pmid":"23284683","id":"PMC_23284683","title":"Roles for NHERF1 and NHERF2 on the regulation of C3a receptor signaling in human mast cells.","date":"2012","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/23284683","citation_count":13,"is_preprint":false},{"pmid":"28869532","id":"PMC_28869532","title":"CFTR-NHERF2-LPA₂ Complex in the Airway and Gut Epithelia.","date":"2017","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/28869532","citation_count":12,"is_preprint":false},{"pmid":"28669731","id":"PMC_28669731","title":"NHERF1 and NHERF2 regulation of SR-B1 stability via ubiquitination and proteasome degradation.","date":"2017","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/28669731","citation_count":12,"is_preprint":false},{"pmid":"24364877","id":"PMC_24364877","title":"NHERF2 is crucial in ERM phosphorylation in pulmonary endothelial cells.","date":"2013","source":"Cell communication and signaling : CCS","url":"https://pubmed.ncbi.nlm.nih.gov/24364877","citation_count":12,"is_preprint":false},{"pmid":"20430067","id":"PMC_20430067","title":"GLAST stability and activity are enhanced by interaction with the PDZ scaffold NHERF-2.","date":"2010","source":"Neuroscience letters","url":"https://pubmed.ncbi.nlm.nih.gov/20430067","citation_count":12,"is_preprint":false},{"pmid":"16374813","id":"PMC_16374813","title":"Astrocytic and neuronal localization of the scaffold protein Na+/H+ exchanger regulatory factor 2 (NHERF-2) in mouse brain.","date":"2006","source":"The Journal of comparative neurology","url":"https://pubmed.ncbi.nlm.nih.gov/16374813","citation_count":12,"is_preprint":false},{"pmid":"20720114","id":"PMC_20720114","title":"The scaffold protein NHERF2 determines the coupling of P2Y1 nucleotide and mGluR5 glutamate receptor to different ion channels in neurons.","date":"2010","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/20720114","citation_count":11,"is_preprint":false},{"pmid":"24613836","id":"PMC_24613836","title":"Structural insights into PDZ-mediated interaction of NHERF2 and LPA(2), a cellular event implicated in CFTR channel regulation.","date":"2014","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/24613836","citation_count":11,"is_preprint":false},{"pmid":"21427361","id":"PMC_21427361","title":"Alterations in the proteome of the NHERF2 knockout mouse jejunal brush border membrane vesicles.","date":"2011","source":"Physiological genomics","url":"https://pubmed.ncbi.nlm.nih.gov/21427361","citation_count":10,"is_preprint":false},{"pmid":"21980575","id":"PMC_21980575","title":"Regulation of apical membrane enrichment and retention of plasma membrane Ca ATPase splice variants by the PDZ-domain protein NHERF2.","date":"2011","source":"Communicative & integrative biology","url":"https://pubmed.ncbi.nlm.nih.gov/21980575","citation_count":10,"is_preprint":false},{"pmid":"23200831","id":"PMC_23200831","title":"Modulatory roles of NHERF1 and NHERF2 in cell surface expression of the glutamate transporter GLAST.","date":"2012","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/23200831","citation_count":9,"is_preprint":false},{"pmid":"21187068","id":"PMC_21187068","title":"Concerted actions of NHERF2 and WNK4 in regulating TRPV5.","date":"2010","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/21187068","citation_count":9,"is_preprint":false},{"pmid":"26251448","id":"PMC_26251448","title":"The NHERF2 sequence adjacent and upstream of the ERM-binding domain affects NHERF2-ezrin binding and dexamethasone stimulated NHE3 activity.","date":"2015","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/26251448","citation_count":8,"is_preprint":false},{"pmid":"19259722","id":"PMC_19259722","title":"Refined genomic localization of the genetic lesion in the osteopetrosis (op) rat and exclusion of three positional and functional candidate genes, Clcn7, Atp6v0c, and Slc9a3r2.","date":"2009","source":"Calcified tissue international","url":"https://pubmed.ncbi.nlm.nih.gov/19259722","citation_count":7,"is_preprint":false},{"pmid":"37573425","id":"PMC_37573425","title":"SLC26A3/NHERF2-IκB/NFκB/p65 feedback loop suppresses tumorigenesis and metastasis in colorectal cancer.","date":"2023","source":"Oncogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/37573425","citation_count":6,"is_preprint":false},{"pmid":"26310448","id":"PMC_26310448","title":"The function and dynamics of the apical scaffolding protein E3KARP are regulated by cell-cycle phosphorylation.","date":"2015","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/26310448","citation_count":4,"is_preprint":false},{"pmid":"39940923","id":"PMC_39940923","title":"NHERF2 as a Novel Biomarker for Distinguishing MAC Pulmonary Disease from Tuberculosis Based on Proteome Analysis of Serum Extracellular Vesicles.","date":"2025","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/39940923","citation_count":4,"is_preprint":false},{"pmid":"37623973","id":"PMC_37623973","title":"HPV16 Impacts NHERF2 Expression in Oropharyngeal Cancers.","date":"2023","source":"Pathogens (Basel, Switzerland)","url":"https://pubmed.ncbi.nlm.nih.gov/37623973","citation_count":2,"is_preprint":false},{"pmid":"21457650","id":"PMC_21457650","title":"A novel porcine gene--SLC9A3R2, differentially expressed in the longissimus muscle tissues from Meishan and Large White pigs.","date":"2011","source":"Folia biologica","url":"https://pubmed.ncbi.nlm.nih.gov/21457650","citation_count":2,"is_preprint":false},{"pmid":"38533975","id":"PMC_38533975","title":"cGMP-dependent kinase 2, Na+/H+ exchanger NHE3, and PDZ-adaptor NHERF2 co-assemble in apical membrane microdomains.","date":"2024","source":"Acta physiologica (Oxford, England)","url":"https://pubmed.ncbi.nlm.nih.gov/38533975","citation_count":1,"is_preprint":false},{"pmid":"15721789","id":"PMC_15721789","title":"Overexpression, purification, and characterization of PDZ domain proteins NHERF and E3KARP in Escherichia coli.","date":"2005","source":"Protein expression and purification","url":"https://pubmed.ncbi.nlm.nih.gov/15721789","citation_count":1,"is_preprint":false},{"pmid":"42179786","id":"PMC_42179786","title":"Multi-omics Data Reveal SLC9A3R2 Promotes Breast Cancer Progression and an Immunosuppressive Microenvironment.","date":"2026","source":"Journal of Cancer","url":"https://pubmed.ncbi.nlm.nih.gov/42179786","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":43659,"output_tokens":12236,"usd":0.157258,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":23314,"output_tokens":7307,"usd":0.149622,"stage2_stop_reason":"end_turn"},"total_usd":0.30688,"stage1_batch_id":"msgbatch_013a8chtv3AWyTqv4z4sEF4C","stage2_batch_id":"msgbatch_01AHsuW63vinsvuTgzmQ3n62","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1998,\n      \"finding\": \"NHERF2 (E3KARP) directly binds NHE3 via its second PDZ domain (plus C-terminal domain), and also binds the cytoskeletal protein ezrin via its C-terminal domain, forming a scaffold that localizes PKA near NHE3 to enable cAMP-dependent inhibition of NHE3.\",\n      \"method\": \"In vitro binding assays, co-localization in PS120 fibroblasts\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — direct in vitro binding assays with domain mapping, replicated across two papers (PMID:9748260, PMID:9792717) using orthogonal methods (in vitro binding + co-immunoprecipitation + functional NHE3 activity assay)\",\n      \"pmids\": [\"9748260\", \"9792717\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"NHERF2 (E3KARP) is not phosphorylated by cAMP/PKA and does not change phosphorylation state upon 8-bromo-cAMP treatment; it functions as an adapter (not a direct PKA substrate) linking NHE3 to ezrin to localize PKA type II near NHE3.\",\n      \"method\": \"In vivo phosphorylation studies, co-immunoprecipitation in opossum kidney cells\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal co-IP plus in vivo phosphorylation assay in a single lab, two orthogonal methods\",\n      \"pmids\": [\"9792717\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"NHERF2 (E3KARP) associates with CFTR preferentially through CFTR's PDZ-binding motif and E3KARP's second PDZ domain with nanomolar affinity; E3KARP also associates with ezrin in vivo, and co-expression of CFTR with E3KARP and ezrin in Xenopus oocytes potentiates cAMP-stimulated CFTR Cl⁻ currents.\",\n      \"method\": \"Co-immunoprecipitation, confocal microscopy, cell fractionation, Xenopus oocyte electrophysiology\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — nanomolar affinity binding assay, co-IP, functional reconstitution in oocytes, multiple orthogonal methods in single study\",\n      \"pmids\": [\"10893422\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"SGK1 specifically interacts with PDZ domains of NHERF2 (but not NHERF1) to mediate glucocorticoid/dexamethasone activation of NHE3; kinase-dead SGK1 blocked NHE3 activation, demonstrating NHERF2 acts as a scaffold linking SGK1 to NHE3.\",\n      \"method\": \"Co-expression in PS120 fibroblasts and opossum kidney cells, dominant-negative kinase-dead SGK1, NHE3 activity assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — dominant-negative mutagenesis plus functional NHE3 activity assay, replicated in two cell lines with specific NHERF2 requirement demonstrated\",\n      \"pmids\": [\"11751930\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"NHERF-2 PDZ domains robustly self-associate (homo-oligomerize) without requiring additional proteins, and NHERF-1 and NHERF-2 form hetero-oligomers in cells via their PDZ domains; NHERF-2 oligomerization is not regulated by phosphorylation (unlike NHERF-1).\",\n      \"method\": \"Purified PDZ domain association assays, co-immunoprecipitation with differentially tagged constructs\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vitro purified protein assay plus cellular co-IP, single lab, two orthogonal methods\",\n      \"pmids\": [\"11456497\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Ca²⁺-dependent inhibition of NHE3 requires E3KARP (NHERF2) specifically (not NHERF1), and occurs via Ca²⁺-dependent association of alpha-actinin-4 with E3KARP through alpha-actinin-4's actin-binding domain plus spectrin repeat domain, leading to NHE3 oligomerization and endocytosis.\",\n      \"method\": \"Stable transfection of PS120 fibroblasts, NHE3 activity assays, co-immunoprecipitation, dominant-negative overexpression, surface biotinylation\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (activity assay, co-IP, dominant-negative, surface biotinylation), specific domain mapping, single lab\",\n      \"pmids\": [\"11948184\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"NHERF2 (E3KARP) binds the DRA (downregulated in adenoma) Cl⁻/HCO₃⁻ exchanger's C-terminal ETKF motif via the second PDZ domain, potentially linking parallel NHE3 and DRA transporters in the apical membrane.\",\n      \"method\": \"In vitro PDZ binding assays with GST fusion proteins, immunofluorescence co-localization in human proximal colon\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vitro binding with domain mutagenesis plus immunofluorescence co-localization, single lab\",\n      \"pmids\": [\"12369822\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Adenosine A2b receptor co-immunoprecipitates with E3KARP (NHERF2) and ezrin upon agonist stimulation; the A2bR is recruited to the plasma membrane and caveolar fractions upon agonist stimulation in intestinal epithelial cells.\",\n      \"method\": \"Co-immunoprecipitation from T84 and Caco2-BBE cells, confocal microscopy\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — co-IP confirmed in two cell lines but single lab, agonist-dependent interaction demonstrated\",\n      \"pmids\": [\"12080047\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"NHERF2 and SGK1 synergize to increase ROMK1 K⁺ channel activity by enhancing channel abundance in the plasma membrane; neither NHERF2 nor SGK1 alone affects ROMK1, but their combination markedly increases K⁺ channel activity and slows decay after brefeldin inhibition.\",\n      \"method\": \"Xenopus oocyte co-expression, electrophysiology, brefeldin A experiments\",\n      \"journal\": \"Journal of the American Society of Nephrology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reconstitution in oocytes with electrophysiology, brefeldin A trafficking assay, single lab\",\n      \"pmids\": [\"12444200\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"PKCα binds specifically to the PDZ1 domain of E3KARP (NHERF2) in a Ca²⁺-dependent manner; PKCα is necessary for Ca²⁺-dependent decrease in plasma membrane NHE3 (endocytosis) but not for NHE3 oligomerization.\",\n      \"method\": \"GST pulldown, co-immunoprecipitation, PKC inhibitors, surface biotinylation in PS120/NHE3/E3KARP cells\",\n      \"journal\": \"American journal of physiology. Cell physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — GST pulldown with domain specificity plus cellular co-IP plus functional activity assay, multiple orthogonal methods, single lab\",\n      \"pmids\": [\"12954600\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"LPA receptor LPA2 (but not other LPA receptors) specifically interacts with NHERF2 via LPA2's C-terminal PDZ-binding motif and NHERF2's second PDZ domain; NHERF2 indirectly links LPA2 to PLC-β3 forming a ternary complex that specifically activates PLC-β3 and downstream ERK/COX-2 signaling.\",\n      \"method\": \"Co-immunoprecipitation, PDZ domain binding assays, siRNA knockdown of NHERF2 and PLC-β3, stable NHERF2 expression, inositol phosphate assay\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (co-IP, PDZ mutants, siRNA, functional PLC assay), specific isoform selectivity demonstrated, single lab\",\n      \"pmids\": [\"15143197\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"NHERF2 (E3KARP) mediates LPA-induced stimulation of NHE3 by enabling LPA-induced PLC activation and subsequent intracellular Ca²⁺ elevation, which drives exocytic trafficking of NHE3 to the apical membrane in a PKC-independent manner.\",\n      \"method\": \"PLC inhibitor (U73122), Ca²⁺ chelator (BAPTA-AM), PKC inhibitor, NHE3 activity and surface amount in OK cells stably expressing E3KARP\",\n      \"journal\": \"Biochimica et biophysica acta\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple pharmacological inhibitors with functional NHE3 activity and surface abundance readouts, single lab\",\n      \"pmids\": [\"15238220\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"NHERF2 co-immunoprecipitates with TRPC4 (but not TRPC5) from renal medullary lysates and they co-localize in descending vasa recta endothelial cells and pericytes.\",\n      \"method\": \"RT-PCR, immunohistochemistry, reciprocal co-immunoprecipitation from renal medullary lysates\",\n      \"journal\": \"American journal of physiology. Cell physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal co-IP from native tissue plus co-localization, single lab\",\n      \"pmids\": [\"15590898\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"NHERF2 is required for cGMP inhibition of NHE3 (while NHERF1 is not); NHERF2 acts as a novel protein kinase G-anchoring protein, binding cGKII via its PDZ2 C-terminus, and membrane myristoylation of cGKII is additionally required for NHE3 inhibition.\",\n      \"method\": \"Co-expression in PS120 cells, in vitro NHERF2-cGKII binding, non-myristoylated cGKII mutant, NHE3 activity assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro binding with domain specificity, myristoylation mutant, functional NHE3 activity assay, specific NHERF2 vs NHERF1 selectivity, single lab with multiple orthogonal approaches\",\n      \"pmids\": [\"15722341\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"NHERF-2 specifically interacts with the P2Y1 receptor C-terminus via NHERF-2's second PDZ domain; this interaction tethers P2Y1R to PLC-β and prolongs P2Y1R-mediated Ca²⁺ signaling in glial cells; point mutations disrupting the P2Y1R-NHERF-2 interaction attenuate the duration of Ca²⁺ responses.\",\n      \"method\": \"PDZ domain proteomic array screen, co-immunoprecipitation, confocal microscopy, functional Ca²⁺ signaling assays with point mutants\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — array screen plus co-IP plus functional mutagenesis, multiple orthogonal methods demonstrating mechanism\",\n      \"pmids\": [\"15901899\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Podocalyxin (gp135) and NHERF-2 co-localize at a preapical subdomain in single MDCK cells and in terminally polarized apical membranes; the PDZ-binding motif of podocalyxin is required for this apical targeting, and depleting podocalyxin by RNAi causes defects in epithelial polarization.\",\n      \"method\": \"Domain deletion mutants, RNA interference of podocalyxin, confocal microscopy in MDCK cells\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — PDZ motif domain mutants plus RNAi with polarization phenotype, single lab\",\n      \"pmids\": [\"15642748\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"NHERF2's second PDZ domain is required for SGK1/NHERF2-mediated stabilization of TRPV5 at the plasma membrane; the TRPV5 C-tail interacts with NHERF2 in a Ca²⁺-independent manner.\",\n      \"method\": \"Pull-down assays, PDZ domain deletion mutants, chemiluminescence surface abundance assay, Xenopus oocyte electrophysiology\",\n      \"journal\": \"Cellular physiology and biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — PDZ domain deletion mutants with functional electrophysiology readout plus pulldown, single lab\",\n      \"pmids\": [\"15665527\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"SIP-1/NHERF2 interacts with mouse SRY via the PDZ1 domain (involving an internal SRY domain rather than C-terminus as in human SRY), and both mouse and human SRY induce nuclear accumulation of NHERF2 in cultured cells; NHERF2 and SRY are co-expressed in the nucleus of pre-Sertoli cells during testis determination.\",\n      \"method\": \"Co-immunoprecipitation/interaction assays, nuclear accumulation assays in cultured cells, GFP-Sry transgenic mice for co-expression analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — protein interaction assays plus nuclear localization experiments and in vivo co-expression, single lab\",\n      \"pmids\": [\"16166090\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"NHERF-2 specifically interacts with mGluR5 (not mGluR1a) via NHERF-2's second PDZ domain; co-expression prolongs mGluR5-mediated Ca²⁺ mobilization and potentiates mGluR5-mediated cell death; a single point mutation in mGluR5-CT abolishes the interaction and attenuates these effects.\",\n      \"method\": \"PDZ domain proteomic array, co-immunoprecipitation, confocal microscopy, functional Ca²⁺ signaling assays with point mutants, cell death assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — PDZ array plus co-IP plus mutagenesis plus functional signaling assays, multiple orthogonal methods demonstrating mechanism\",\n      \"pmids\": [\"16891310\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"When NHE3 is co-expressed with CFTR, NHE3 sequesters NHERF2's PDZ2 domain, which prevents PDZ2 from participating in PKA-dependent apical CFTR expression and activation; deletion of NHERF2 binding domains inhibits PKA-dependent apical CFTR expression.\",\n      \"method\": \"NHERF2 PDZ domain deletion constructs, functional CFTR activity assays in A6-NHE3 cell monolayers\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — PDZ domain deletion mutants with functional CFTR assay, single lab\",\n      \"pmids\": [\"16824484\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"NHERF2 (but not NHERF1) specifically enhances PEPT2 function and surface abundance via the PEPT2 C-terminal PDZ-binding motif; NHERF2 stabilizes PEPT2 at the cell surface (demonstrated by dynasore experiments) and acts together with SGK1 which phosphorylates PEPT2 at Ser185.\",\n      \"method\": \"Xenopus oocyte electrophysiology, surface abundance immunoassay, C-terminal deletion mutant, dynasore endocytosis inhibition\",\n      \"journal\": \"Cellular physiology and biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional electrophysiology plus surface abundance assay plus pharmacological endocytosis block, single lab\",\n      \"pmids\": [\"19088452\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"NHERF2 confers inhibitory LPA receptor signaling to CFTR in duodenum; in Nherf2⁻/⁻ mice, FSK-stimulated HCO₃⁻ secretion is augmented, and LPA-mediated inhibition of CFTR-dependent secretion is abolished, demonstrating NHERF2 couples the LPA receptor to CFTR to provide inhibitory signals.\",\n      \"method\": \"Nherf2 knockout mouse model, duodenal HCO₃⁻ secretion measurements, laser microdissection and quantitative PCR\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — in vivo genetic knockout with quantitative physiological readout, confirmed in multiple NHERF knockout models in same study\",\n      \"pmids\": [\"19221439\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"LPA stimulates NHE3 and intestinal fluid absorption via the LPA5 receptor, and this stimulation requires NHERF2 which interacts with LPA5; LPA-mediated intestinal fluid absorption is absent in Nherf2⁻/⁻ mice but preserved in Lpa2⁻/⁻ mice; LPA increases NHE3 protein abundance at the brush border.\",\n      \"method\": \"Nherf2⁻/⁻ and Lpa2⁻/⁻ knockout mice, intestinal fluid absorption measurements, heterologous expression of LPA5 with NHERF2\",\n      \"journal\": \"Gastroenterology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic knockout mouse model with quantitative fluid absorption assays plus heterologous reconstitution, multiple orthogonal approaches\",\n      \"pmids\": [\"19800338\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"NHERF2 silencing in endothelial cells causes hyperproliferation even without mitogens, associated with increased cytoplasmic calcium, increased c-Myc and cyclin D1, and reduced p27; NHERF2 is thus a negative regulator of endothelial proliferation.\",\n      \"method\": \"siRNA knockdown, cell proliferation assays, cell cycle analysis, mouse hemangioma model\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA knockdown with multiple molecular readouts and in vivo mouse model, single lab\",\n      \"pmids\": [\"22343917\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"MAGI-3 competes with NHERF-2 for binding to LPA2 and PLC-β3; NHERF-2 promotes LPA2-Gαq coupling and stimulates PLC activity and cell migration, while MAGI-3 promotes LPA2-Gα12 coupling and inhibits NF-κB/JNK signaling, demonstrating NHERF-2 determines G-protein coupling specificity of LPA2.\",\n      \"method\": \"Overexpression and knockdown of MAGI-3 in HCT116/SW480 cells, co-immunoprecipitation, migration/invasion assays, inositol phosphate and NF-κB assays\",\n      \"journal\": \"Gastroenterology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — competitive binding, co-IP, and multiple functional readouts (migration, invasion, IP, NF-κB), single lab with multiple orthogonal methods\",\n      \"pmids\": [\"21134377\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"NHERF2 binding to NHE3 in brush borders is dynamic; LPA stimulation transiently dissociates the NHERF2-NHE3 complex (loss of co-precipitation and FRET signal at 30 min, re-established at 50-60 min), increasing NHE3 mobility via a PI3K-dependent exocytic pathway and a PI3K-independent dissociation from NHERF2.\",\n      \"method\": \"FRAP, acceptor photobleaching FRET, co-immunoprecipitation, PI3K inhibitor LY294002 in OK cells stably expressing NHERF2\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — FRET, FRAP, and co-IP as three orthogonal methods demonstrating dynamic interaction, pharmacological dissection of pathway\",\n      \"pmids\": [\"20571054\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"NHERF2 ablation in murine intestine shifts NHE3 localization from the terminal web to microvilli and abolishes Ca²⁺-ionophore- and carbachol-mediated inhibition of NHE3, as well as STp (cGMP-mediated) inhibition, while forskolin-induced inhibition is preserved; NHERF2 tethers NHE3 near the terminal web.\",\n      \"method\": \"NHERF2 knockout mice, fluorometric NHE3 activity assay, immunolocalization, knockout validation\",\n      \"journal\": \"The Journal of physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — in vivo genetic knockout with quantitative NHE3 activity and localization readouts, independently confirmed in related study\",\n      \"pmids\": [\"20962002\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"NHERF2 apical scaffolding enhances apical localization of PMCA2w/b in polarized MDCK cells by anchoring the pump to the apical actin cytoskeleton via ezrin, reducing pump internalization and lateral mobility; PMCA2x/b remains basolateral even with NHERF2 overexpression.\",\n      \"method\": \"Co-expression in polarized MDCK cells, surface biotinylation, FRAP, cytochalasin D/latrunculin B actin disruption, co-localization with ezrin\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — surface biotinylation plus FRAP plus actin disruption experiments, multiple orthogonal methods in polarized cell system\",\n      \"pmids\": [\"20663896\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"NHERF-2 knockdown in astrocytes reduces GLAST glutamate transporter activity and protein half-life; endogenous GLAST and NHERF-2 robustly co-immunoprecipitate; the interaction is dependent on the last amino acid of GLAST's C-terminus.\",\n      \"method\": \"siRNA knockdown, co-immunoprecipitation with C-terminal deletion mutants, pulse-chase metabolic labeling, glutamate uptake assay\",\n      \"journal\": \"Neuroscience letters\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — native co-IP plus siRNA with functional transporter activity plus pulse-chase stability assay, multiple orthogonal methods\",\n      \"pmids\": [\"20430067\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"NHERF2 expression restricts P2Y1R and mGluR5 coupling to CaV2.2 calcium channels in sympathetic neurons without affecting M-current inhibition; this selective restriction requires the NHERF2-binding motif on the receptors, demonstrating NHERF2 determines receptor-to-ion-channel coupling specificity.\",\n      \"method\": \"Intranuclear cDNA injection in sympathetic neurons, electrophysiology of M-current and N-type Ca²⁺ current, P2Y1R DTSL-motif deletion mutant\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — PDZ-binding motif deletion mutant plus electrophysiological functional assay in primary neurons, selectivity confirmed with non-binding receptor control\",\n      \"pmids\": [\"20720114\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"NHERF2 and NHERF3 form the strongest heterodimerization among all NHERF family pairs; this heterodimerization requires NHERF2's PDZ domains and NHERF3's C-terminal PDZ recognition motif; the NHERF3-4A mutant defective in heterodimerization does not support carbachol-induced NHE3 inhibition.\",\n      \"method\": \"Pulldown, co-immunoprecipitation, FRET, FRAP, functional NHE3 inhibition assay with NHERF3-4A mutant\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (pulldown, co-IP, FRET, FRAP, functional assay with mutant), single lab\",\n      \"pmids\": [\"24867958\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"NHERF2 is necessary for normal basal NHE3 activity and apical localization in mouse distal ileum; NHERF2-null ileum shows reduced brush border NHE3, and cAMP, cGMP, and Ca²⁺ (UTP) all fail to inhibit NHE3, while hyperosmolar inhibition is preserved; LPA stimulation of NHE3 is NHERF2-dependent.\",\n      \"method\": \"NHERF2-null mouse model, two-photon microscopy/SNARF-4F NHE3 activity assay, immunofluorescence\",\n      \"journal\": \"American journal of physiology. Cell physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — in vivo genetic knockout with quantitative two-photon microscopy NHE3 activity and localization measurements, multiple second messenger pathways tested\",\n      \"pmids\": [\"21430287\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Elevated intracellular Ca²⁺ acutely abolishes the NHERF2-NHE3 FRET signal within 1 min in opossum kidney cell microvilli, transiently increasing NHE3 mobility; the association is re-established by ~60 min; NHERF1-NHE3 association is not disrupted by elevated Ca²⁺.\",\n      \"method\": \"FRET (acceptor photobleaching), FRAP, co-immunoprecipitation in polarized OK cells\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — FRET plus FRAP plus co-IP, three orthogonal methods demonstrating dynamic Ca²⁺-dependent NHERF2-NHE3 dissociation\",\n      \"pmids\": [\"21799002\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"CaMKII inhibits basal NHE3 activity by a NHERF2-dependent process; CaMKIIγ constitutively binds NHE3 between aa 586-605 in a Ca²⁺-dependent manner (less association when Ca²⁺ is elevated); CaMKII phosphorylates NHE3 under basal conditions at sites downstream of aa 690.\",\n      \"method\": \"CaMKII inhibitors (KN-93, KN-62), co-immunoprecipitation domain mapping, back phosphorylation assay, NHERF2 requirement established by cell model\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — phosphorylation assay plus domain mapping co-IP plus pharmacological inhibitors, multiple orthogonal methods in single study\",\n      \"pmids\": [\"22371496\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"NHERF2 scaffolds a megalin-ClC-5 complex in proximal tubule cells; NHERF2 interacts with megalin via an internal NHERF binding domain in megalin's C-terminus and PDZ2 of NHERF2; siRNA silencing of NHERF2 abolishes the megalin-ClC-5 interaction without affecting megalin protein levels.\",\n      \"method\": \"GST pulldown, immunoprecipitation from rat kidney lysate, siRNA knockdown, fusion protein reconstitution\",\n      \"journal\": \"The international journal of biochemistry & cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with fusion proteins plus native tissue co-IP plus siRNA, multiple orthogonal methods\",\n      \"pmids\": [\"22349218\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"NHERF2 is more slowly mobile in brush border microvilli than NHERF1 or NHERF3; its slower mobility is determined by a unique C-terminal domain (including a non-conserved region plus ERM-binding domain); this C-terminal domain is also required for LPA stimulation of NHE3 activity/mobility and Ca²⁺ ionophore inhibition of NHE3.\",\n      \"method\": \"FRAP/confocal microscopy, chimeras and point mutants of NHERF1/2, functional NHE3 activity assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — FRAP with chimeric domain-swap mutants plus functional NHE3 assays, unique domain identified\",\n      \"pmids\": [\"23612977\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"E3KARP (NHERF2) localizes to the base of microvilli (not along the full length like EBP50/NHERF1); this differential localization is determined by E3KARP's tail region; E3KARP exchanges more slowly from microvilli than EBP50, and this difference is also tail-determined.\",\n      \"method\": \"FRAP in live epithelial cells, chimeric tail constructs, proteomic pulldown\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — FRAP plus chimeric construct analysis plus proteomic data, single lab\",\n      \"pmids\": [\"23985317\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"LPA stimulation of NHE3 exocytosis requires NHERF2, and operates through an ERK-PLC-PKCδ signaling module that dynamically and reversibly releases NHE3 from NHERF2; PKCδ is necessary for LPA-stimulated NHE3 mobility and NHE3/NHERF2 dissociation.\",\n      \"method\": \"FRAP, co-immunoprecipitation, PKCδ knockdown, ERK and PLC inhibitors, NHE3 activity in OK cells\",\n      \"journal\": \"American journal of physiology. Cell physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — FRAP plus co-IP plus genetic knockdown plus pharmacological inhibitors, pathway ordering established\",\n      \"pmids\": [\"24760985\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"NHERF2 interacts with estrogen receptor alpha (ERα) predominantly at the AF-1 domain and acts as a coactivator; overexpression of NHERF2 in MCF7 cells increases ERα transactivation, and NHERF2 together with SRC-1 synergistically enhances ERα activity at target gene promoters.\",\n      \"method\": \"Co-immunoprecipitation, ChIP at ERα target gene promoters, ERα transactivation reporter assays, stable overexpression in MCF7\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP plus ChIP plus functional reporter assay, single lab\",\n      \"pmids\": [\"24771346\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Crystal structure of NHERF2 PDZ1 domain in complex with LPA2 C-terminal peptide reveals that binding specificity is achieved through hydrogen bonds and hydrophobic contacts with the last four LPA2 residues; a small surface pocket adjacent to the ligand-binding site was identified.\",\n      \"method\": \"X-ray crystallography of PDZ1-LPA2 complex\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structure determination, single lab but direct structural evidence\",\n      \"pmids\": [\"24613836\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"NHERF2 forms a complex with SCHIP1 and ezrin in podocyte foot processes; this complex is associated with cortical actin cytoskeleton dynamics in response to PDGF-BB signaling.\",\n      \"method\": \"Co-immunoprecipitation in cultured podocytes, immunofluorescence, zebrafish morpholino knockdown\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — co-IP in cultured cells plus in vivo zebrafish model, single lab\",\n      \"pmids\": [\"25807495\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"NHERF2 contains an ERM-binding regulatory sequence (EBRS) located 19 residues upstream of the ERM-binding domain (EBD); EBRS facilitates NHERF2-ezrin interaction and is necessary for exclusive apical NHERF2 distribution in OK cells; phosphorylation of Ser303 in the EBRS decreases ezrin-binding affinity, dislocates NHERF2 to cytosol, increases NHERF2 mobility, and prevents dexamethasone stimulation of NHE3.\",\n      \"method\": \"EBRS deletion/point mutants, FRAP, co-immunoprecipitation with ezrin, phosphomimetic Ser303 mutants, NHE3 activity assays\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — domain deletion plus phosphomimetic mutants plus FRAP plus functional NHE3 assay, multiple orthogonal methods\",\n      \"pmids\": [\"26251448\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"E3KARP (NHERF2) exchange rate from microvilli is greatly enhanced during mitosis due to phosphorylation of Ser303 in its tail; A-Raf is required for Ser303 phosphorylation in mitotic cells; the S303D phosphomimetic mutation prevents E3KARP from substituting for EBP50 in microvillus formation.\",\n      \"method\": \"FRAP in mitotic cells, A-Raf RNAi, S303D phosphomimetic mutant, microvillus formation assay\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — FRAP plus genetic RNAi plus phosphomimetic mutant with functional microvillus assay, identifies kinase writer for Ser303\",\n      \"pmids\": [\"26310448\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Loss of NHERF1 and NHERF2 in human mast cells does not affect C3aR desensitization, internalization, ERK/Akt phosphorylation, or chemotaxis, but does inhibit C3a-induced degranulation, NF-κB activation, and chemokine production; C3aR does not associate with NHERF1 or NHERF2 despite having a PDZ motif.\",\n      \"method\": \"Lentiviral shRNA knockdown in human mast cells, functional degranulation, NF-κB and chemokine assays, co-immunoprecipitation (negative result for C3aR association)\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — stable shRNA knockdown with multiple functional readouts; negative C3aR-NHERF2 association is noteworthy\",\n      \"pmids\": [\"23284683\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"HPV-16 and HPV-18 E6 oncoproteins interact with NHERF-2 via their PDZ-binding motifs and target NHERF-2 for proteasome-mediated degradation; E6-mediated NHERF-2 degradation leads to p27 downregulation and cyclin D1 upregulation, accelerating cell proliferation.\",\n      \"method\": \"Co-immunoprecipitation, proteasome inhibitor experiments, E6 PBM point mutants, NHERF-2 degradation assays in HPV-positive cervical tumor cells\",\n      \"journal\": \"Journal of virology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — co-IP plus mutagenesis plus proteasome inhibitor rescue plus functional proliferation assays in HPV-positive cancer cells\",\n      \"pmids\": [\"31597772\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"NHERF2 stabilizes IκB protein by reducing its ubiquitination; SLC26A3 augments the NHERF2-IκB interaction, thereby inhibiting p65 nuclear translocation and NF-κB activity in colorectal cancer cells.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assays, NF-κB reporter assays, p65 nuclear/cytoplasmic fractionation\",\n      \"journal\": \"Oncogenesis\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP plus ubiquitination assay plus functional NF-κB readout, single lab\",\n      \"pmids\": [\"37573425\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"NHE3, NHERF2, and cGKII co-assemble in lipid raft microdomains of the small intestinal brush border membrane; NHERF2 is required for NHE3 raft association; Gucy2c activation decreases NHE3 raft association and shifts NHE3 from microvilli to terminal web in a cGKII- and NHERF2-dependent manner.\",\n      \"method\": \"Optiprep density gradient fractionation of Triton X-solubilized brush border membranes, NHERF2- and cGKII-knockout mice, confocal microscopy\",\n      \"journal\": \"Acta physiologica\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — lipid raft fractionation plus multiple knockout mouse models (NHE3, cGKII, NHERF2) with localization readout\",\n      \"pmids\": [\"38533975\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"NHERF2 is necessary for agonist-induced ERM phosphorylation in pulmonary artery endothelial cells; NHERF2 associates with all three ERM proteins and co-immunoprecipitates with Rho kinase 2 (ROCK2); NHERF2 depletion prevents ROCK2-ERM association; a NHERF2 mutant unable to bind ERM attenuates cell attachment.\",\n      \"method\": \"Co-immunoprecipitation, siRNA knockdown, NHERF2 ERM-binding mutant, ECIS cell attachment measurement, Matrigel tube formation\",\n      \"journal\": \"Cell communication and signaling\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP plus siRNA plus binding mutant plus functional assay, single lab\",\n      \"pmids\": [\"24364877\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"NHERF2 is required for cGMP- and Ca²⁺-dependent but not cAMP-dependent inhibition of NHE3 in Caco-2/bbe cells; simultaneous knockdown of both NHERF1 and NHERF2 is required to abolish cAMP inhibition; EGF stimulation of NHE3 is NHERF1-dependent (not NHERF2-dependent).\",\n      \"method\": \"Lentivirus shRNA stable knockdown and adenovirus siRNA transient knockdown in Caco-2/bbe cells, NHE3 activity assays\",\n      \"journal\": \"American journal of physiology. Cell physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — dual stable and transient knockdown approaches, multiple second messenger pathways tested, single lab with rigorous controls\",\n      \"pmids\": [\"21191106\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"NHERF2 and NHERF3 have overlapping requirements in mouse jejunum for NHE3 regulation by LPA (stimulation) and by elevated Ca²⁺ and cGMP (inhibition); glucose-stimulated NHE3 activity is reduced in NHERF2- but not NHERF3-null mice.\",\n      \"method\": \"NHERF2 and NHERF3 knockout mice, two-photon microscopy/SNARF-4F NHE3 activity\",\n      \"journal\": \"American journal of physiology. Gastrointestinal and liver physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — two independent genetic knockouts with quantitative in vivo NHE3 activity, confirms prior findings in different intestinal segment\",\n      \"pmids\": [\"28882822\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"NHERF2 is a dual-PDZ-domain scaffold protein that functions primarily as an apical membrane organizer in epithelial cells, assembling macromolecular signaling complexes by binding NHE3 (via PDZ2), CFTR, LPA receptors (LPA2/LPA5), P2Y1R, mGluR5, and other transporters/receptors through PDZ domain interactions while connecting them to the actin cytoskeleton via an ERM-binding domain that engages ezrin; it serves as a platform for cAMP (PKA), cGMP (cGKII anchoring), and Ca²⁺/PKCα/CaMKII second messenger inhibition of NHE3, for SGK1-mediated stimulation of NHE3 and other transporters (ROMK1, PEPT2, TRPV5), and for LPA5-mediated stimulation of NHE3 via PLC-ERK-PKCδ signaling, with its function dynamically regulated by phosphorylation of Ser303 (by A-Raf during mitosis) in its unique C-terminal region, which decreases ezrin binding and increases microvillar mobility.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"NHERF2 (E3KARP) is a dual-PDZ-domain apical scaffold that organizes macromolecular signaling complexes in polarized epithelia, coupling membrane transporters and receptors to regulatory kinases and to the actin cytoskeleton [#0, #31]. Its second PDZ domain binds the C-terminal PDZ motifs of the Na+/H+ exchanger NHE3, CFTR, the Cl-/HCO3- exchanger DRA, the LPA2 receptor, P2Y1R, mGluR5, and other transporters with high affinity, while a C-terminal ERM-binding domain engages ezrin to tether these complexes near the apical actin cortex [#0, #2, #6, #10, #14, #39]. Through this platform NHERF2 specifically (and distinctly from NHERF1) localizes second-messenger machinery to NHE3: it anchors PKA-, cGMP-dependent protein kinase II (cGKII), Ca2+/PKCalpha, and CaMKII signaling for NHE3 inhibition, and SGK1 for stimulation of NHE3 and other transporters including ROMK1, PEPT2, and TRPV5 [#0, #3, #9, #13, #33, #16, #20, #8]. NHERF2 also controls receptor output by determining G-protein coupling and effector specificity, linking LPA2 to PLCbeta3/ERK/COX-2 signaling and restricting P2Y1R/mGluR5 coupling to CaV2.2 channels [#10, #24, #29]. Knockout mouse studies establish that NHERF2 is required in intestine for basal NHE3 apical localization and for cGMP-, Ca2+-, and LPA-mediated regulation of NHE3 and CFTR-dependent secretion, tethering NHE3 near the terminal web and within brush-border lipid rafts [#21, #22, #26, #31, #46]. The interaction is dynamic: elevated Ca2+ or LPA stimulation (via an ERK-PLC-PKCdelta module) transiently dissociates the NHERF2-NHE3 complex to increase exchanger mobility, and phosphorylation of Ser303 in NHERF2's unique C-terminal ERM-binding regulatory sequence by A-Raf during mitosis reduces ezrin binding and releases NHERF2 into the cytosol [#32, #37, #41, #42]. Beyond epithelial transport, NHERF2 acts as a negative regulator of endothelial proliferation and is targeted for degradation by HPV E6 oncoproteins, linking its loss to p27/cyclin D1 dysregulation [#23, #44].\",\n  \"teleology\": [\n    {\n      \"year\": 1998,\n      \"claim\": \"Established the founding scaffold model: how cAMP-dependent regulation of NHE3 is spatially organized, by showing NHERF2 physically links NHE3 to ezrin and PKA.\",\n      \"evidence\": \"In vitro binding with domain mapping and co-IP in fibroblasts/opossum kidney cells, with NHE3 activity assays\",\n      \"pmids\": [\"9748260\", \"9792717\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not establish whether NHERF2 vs NHERF1 confer distinct selectivity\", \"Direct demonstration of PKA tethering in native epithelium absent\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Defined NHERF2 as a passive adapter rather than a kinase substrate, clarifying that its regulatory role is structural localization of PKA.\",\n      \"evidence\": \"In vivo phosphorylation studies and co-IP in opossum kidney cells\",\n      \"pmids\": [\"9792717\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Did not exclude regulatory phosphorylation by other kinases (later shown at Ser303)\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Extended the scaffold to CFTR, showing NHERF2 functionally potentiates cAMP-stimulated Cl- currents via PDZ2 and ezrin.\",\n      \"evidence\": \"Nanomolar binding assays, co-IP, and Xenopus oocyte electrophysiology\",\n      \"pmids\": [\"10893422\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological context of CFTR regulation not yet tested in epithelium\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Identified NHERF2 as the specific scaffold (vs NHERF1) coupling the kinase SGK1 to NHE3, explaining glucocorticoid activation of the exchanger.\",\n      \"evidence\": \"Co-expression with dominant-negative kinase-dead SGK1 and NHE3 activity assays in two cell lines\",\n      \"pmids\": [\"11751930\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct SGK1 phosphorylation site on NHE3 or NHERF2 not mapped here\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Showed NHERF2 self- and hetero-oligomerizes via PDZ domains, indicating scaffolds can multimerize to assemble larger complexes.\",\n      \"evidence\": \"Purified PDZ domain association assays and co-IP with tagged constructs\",\n      \"pmids\": [\"11456497\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequence of oligomerization on transporter regulation not established\", \"Stoichiometry in vivo unknown\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Resolved the mechanism of Ca2+-dependent NHE3 inhibition: NHERF2 specifically recruits alpha-actinin-4 and PKCalpha to drive NHE3 oligomerization and endocytosis.\",\n      \"evidence\": \"Stable transfection, NHE3 activity, co-IP, dominant-negative, and surface biotinylation in PS120 cells\",\n      \"pmids\": [\"11948184\", \"12954600\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether oligomerization precedes or follows endocytosis not fully ordered\", \"alpha-actinin-4 recruitment trigger details incomplete\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Broadened the apical interactome to include the DRA Cl-/HCO3- exchanger and adenosine A2b receptor, supporting NHERF2 as a coordinator of parallel transport/receptor systems.\",\n      \"evidence\": \"In vitro PDZ binding with GST fusions and agonist-dependent co-IP in intestinal epithelial cell lines\",\n      \"pmids\": [\"12369822\", \"12080047\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional coupling of DRA and NHE3 via NHERF2 not demonstrated physiologically\", \"A2bR interaction context limited to co-IP\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Demonstrated NHERF2 dictates receptor signaling output by linking LPA2 to PLCbeta3, forming a ternary complex driving ERK/COX-2 signaling.\",\n      \"evidence\": \"Co-IP, PDZ mutants, siRNA knockdown, and inositol phosphate assays with isoform selectivity\",\n      \"pmids\": [\"15143197\", \"15238220\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo relevance not yet established (addressed later by knockouts)\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Established NHERF2 as a protein kinase G anchoring protein, identifying it as required for cGMP (cGKII)-mediated NHE3 inhibition distinct from NHERF1.\",\n      \"evidence\": \"Co-expression, in vitro cGKII binding, non-myristoylated mutant, and NHE3 activity assays\",\n      \"pmids\": [\"15722341\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of cGKII recognition not resolved\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Generalized the receptor-tethering function to neuronal/glial GPCRs (P2Y1R, mGluR5) and to apical polarity (podocalyxin), prolonging Ca2+ signaling and shaping epithelial organization.\",\n      \"evidence\": \"PDZ array screens, co-IP, point-mutant functional Ca2+ assays, and RNAi polarization phenotypes\",\n      \"pmids\": [\"15901899\", \"16891310\", \"15642748\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which NHERF2 prolongs Ca2+ signals (effector retention vs recycling) not fully resolved\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Expanded the SGK1/NHERF2 module to multiple transporters (ROMK1, TRPV5, PEPT2), showing NHERF2 stabilizes surface abundance by limiting endocytosis.\",\n      \"evidence\": \"Xenopus oocyte electrophysiology, surface abundance assays, and dynasore endocytosis block\",\n      \"pmids\": [\"12444200\", \"15665527\", \"19088452\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Native-tissue relevance for these transporters not demonstrated\", \"Direct SGK1 phosphosites variably mapped\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Provided in vivo genetic proof that NHERF2 couples LPA receptors (LPA5, not LPA2) to NHE3 stimulation and to inhibitory LPA-CFTR signaling in intestine.\",\n      \"evidence\": \"Nherf2-/- and Lpa2-/- mice with duodenal HCO3- secretion and intestinal fluid absorption measurements\",\n      \"pmids\": [\"19221439\", \"19800338\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Reconciliation of LPA2 (in vitro) vs LPA5 (in vivo) receptor usage incompletely resolved\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Showed NHERF2 determines LPA2 G-protein coupling specificity by competing with MAGI-3, controlling migration vs NF-kappaB outcomes.\",\n      \"evidence\": \"Competitive binding, co-IP, and migration/invasion/IP/NF-kappaB assays in colorectal cells\",\n      \"pmids\": [\"21134377\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Quantitative stoichiometry of the NHERF2/MAGI-3 competition in vivo unknown\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Revealed the NHERF2-NHE3 interaction is dynamic, with LPA and Ca2+ transiently dissociating the complex to mobilize NHE3 via PI3K-dependent exocytosis.\",\n      \"evidence\": \"FRAP, acceptor-photobleaching FRET, co-IP, and PI3K inhibitor experiments in OK cells\",\n      \"pmids\": [\"20571054\", \"21799002\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular trigger for reassociation at 60 min not identified\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Established NHERF2 as the ezrin-dependent apical anchor for additional targets (PMCA2w/b, GLAST, TRPC4) and as a determinant of receptor-to-channel coupling in neurons.\",\n      \"evidence\": \"Surface biotinylation, FRAP, actin disruption, pulse-chase stability, native co-IP, and neuronal electrophysiology\",\n      \"pmids\": [\"20663896\", \"20430067\", \"15590898\", \"20720114\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether ezrin tethering is required for all of these targets uniformly not established\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Identified NHERF2 as a negative regulator of endothelial proliferation, linking its loss to elevated Ca2+, c-Myc/cyclin D1, and reduced p27.\",\n      \"evidence\": \"siRNA knockdown, proliferation/cell-cycle analysis, and mouse hemangioma model\",\n      \"pmids\": [\"22343917\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism connecting scaffold loss to cell-cycle gene changes not fully defined\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Genetically confirmed NHERF2 is essential for basal NHE3 apical localization and for cAMP/cGMP/Ca2+ regulation across intestinal segments, with selective preservation of hyperosmolar inhibition.\",\n      \"evidence\": \"NHERF2-null mice with two-photon microscopy NHE3 activity and immunofluorescence\",\n      \"pmids\": [\"21430287\", \"20962002\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Redundancy with NHERF3 not yet dissected here\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Added CaMKII and megalin-ClC-5 to the NHERF2-organized network, showing roles in basal NHE3 inhibition and proximal tubule receptor complex assembly.\",\n      \"evidence\": \"Phosphorylation/back-phosphorylation assays, domain-mapping co-IP, GST pulldown, and siRNA in tissue/cell models\",\n      \"pmids\": [\"22371496\", \"22349218\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"CaMKII NHE3 phosphosite location only partially mapped\", \"Functional output of megalin-ClC-5 scaffolding in vivo not measured\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Localized NHERF2's distinctive slow microvillar mobility and base-of-microvillus positioning to its unique C-terminal tail, which is required for LPA stimulation and Ca2+ inhibition of NHE3.\",\n      \"evidence\": \"FRAP with NHERF1/2 chimeras and point mutants, functional NHE3 assays\",\n      \"pmids\": [\"23612977\", \"23985317\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular partners conferring slow exchange not all identified\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Linked NHERF2 to ERM/ROCK2 signaling in endothelium, establishing a role in agonist-induced ERM phosphorylation and cell attachment.\",\n      \"evidence\": \"Co-IP, siRNA, ERM-binding mutant, and ECIS/Matrigel functional assays\",\n      \"pmids\": [\"24364877\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct ROCK2-NHERF2 binding interface not mapped\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Defined the LPA-stimulated NHE3 mobilization pathway as an ERK-PLC-PKCdelta module that reversibly releases NHE3 from NHERF2, and identified a nuclear coactivator role for NHERF2 with ERalpha.\",\n      \"evidence\": \"FRAP, co-IP, PKCdelta knockdown, inhibitor ordering in OK cells; co-IP/ChIP/reporter assays in MCF7\",\n      \"pmids\": [\"24760985\", \"24771346\", \"24613836\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How a predominantly apical scaffold accesses the nucleus for ERalpha coactivation not reconciled\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Identified the Ser303-containing ERM-binding regulatory sequence (EBRS) as the master switch: its phosphorylation by A-Raf during mitosis reduces ezrin binding, relocates NHERF2 to cytosol, and disables SGK1/dexamethasone stimulation of NHE3.\",\n      \"evidence\": \"EBRS/phosphomimetic mutants, FRAP, ezrin co-IP, A-Raf RNAi, and NHE3/microvillus functional assays\",\n      \"pmids\": [\"26251448\", \"26310448\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Phosphatase reversing Ser303 not identified\", \"Signals controlling A-Raf activity toward NHERF2 outside mitosis unknown\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Defined functional redundancy and division of labor between NHERF2 and NHERF3 in intestinal NHE3 regulation, with NHERF2 uniquely required for glucose-stimulated activity.\",\n      \"evidence\": \"NHERF2 and NHERF3 knockout mice with two-photon NHE3 activity; mast cell shRNA functional assays\",\n      \"pmids\": [\"28882822\", \"24867958\", \"23284683\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanistic basis of NHERF2-specific glucose response not defined\", \"C3aR functional effects occur without direct NHERF2 association\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Connected NHERF2 loss to oncogenesis, showing HPV E6 targets it for proteasomal degradation to deregulate p27/cyclin D1, and later that NHERF2 stabilizes IkappaB to restrain NF-kappaB.\",\n      \"evidence\": \"Co-IP, E6 PBM mutants, proteasome inhibitor rescue, ubiquitination and NF-kappaB reporter assays in cancer cells\",\n      \"pmids\": [\"31597772\", \"37573425\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"NHERF2-IkappaB stabilization confirmed in a single study/system\", \"Whether E6-driven degradation operates in primary tumors not established\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Placed the NHE3-NHERF2-cGKII complex in brush-border lipid rafts and showed NHERF2 is required for NHE3 raft association and guanylyl-cyclase-C-triggered redistribution.\",\n      \"evidence\": \"Density-gradient raft fractionation with NHE3, cGKII, and NHERF2 knockout mice and confocal imaging\",\n      \"pmids\": [\"38533975\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Lipid determinants recruiting NHERF2 to rafts not identified\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How NHERF2's apical transport-scaffolding function mechanistically relates to its nuclear (ERalpha, SRY) and tumor-suppressive (IkappaB, p27) roles, and what governs target selection among its many PDZ ligands in a single cell, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unified model linking membrane scaffold vs nuclear functions\", \"Determinants of competitive ligand selection among co-expressed PDZ partners unknown\", \"Structural basis for PDZ2 promiscuity vs PDZ1 selectivity only partially defined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 2, 3, 13, 30]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [5, 10, 24, 29, 33]},\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [0, 27, 47]},\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [38]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 2, 26, 27, 46]},\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [0, 27, 35, 36, 41]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [41]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [17, 38]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-382551\", \"supporting_discovery_ids\": [0, 5, 13, 26, 31]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [10, 14, 18, 24, 29]},\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [20, 27, 16, 36]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [44, 45]}\n    ],\n    \"complexes\": [\n      \"NHE3-NHERF2-ezrin scaffold\",\n      \"LPA2-NHERF2-PLCbeta3 ternary complex\",\n      \"megalin-NHERF2-ClC-5 complex\",\n      \"NHERF2-SCHIP1-ezrin complex\"\n    ],\n    \"partners\": [\n      \"NHE3\",\n      \"EZR\",\n      \"CFTR\",\n      \"SGK1\",\n      \"LPAR2\",\n      \"PRKG2\",\n      \"P2RY1\",\n      \"GRM5\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}