| 2006 |
APPL1 was identified as a direct binding partner of adiponectin receptors AdipoR1 and AdipoR2 via its PTB domain interacting with the intracellular region of the receptors; this interaction is stimulated by adiponectin and mediates downstream signaling including lipid oxidation, glucose uptake, and GLUT4 membrane translocation. APPL1 also stimulates Rab5 interaction upon adiponectin treatment to increase GLUT4 translocation. |
Yeast two-hybrid screen, co-immunoprecipitation, siRNA knockdown, overexpression assays in mammalian cells |
Nature cell biology |
High |
16622416
|
| 2004 |
APPL1 and APPL2 are Rab5 effectors residing on a subpopulation of endosomes; in response to EGF or oxidative stress, APPL1 translocates from endosomal membranes to the nucleus where it interacts with the NuRD/MeCP1 nucleosome remodeling and histone deacetylase complex, thereby linking endosomal signaling to gene expression and cell proliferation. |
Co-immunoprecipitation, subcellular fractionation, live imaging, RNAi knockdown, mass spectrometry |
Cell |
High |
15016378
|
| 2009 |
APPL endosomes represent an early endocytic intermediate derived from clathrin-coated vesicles and macropinosomes; PI3P acts as a switch to convert APPL endosomes into classical Rab5/PI3P-positive endosomes, and depletion of PI3P causes reversion of Rab5-positive endosomes to the APPL stage and enhances growth factor signaling. |
Quantitative single vesicle live imaging, acute pharmacological manipulation of PI3P, PI3P depletion experiments |
Cell |
High |
19303853
|
| 2008 |
In zebrafish, Appl1 regulates Akt activity and substrate specificity from endosomes: it controls GSK-3β phosphorylation but not TSC2, selectively promoting cell survival. Akt and GSK-3β, but not TSC2, dynamically associate with Appl1 endosomes upon growth factor stimulation, and Appl1 function requires its endosomal localization. |
Zebrafish loss-of-function genetics, live imaging, epistasis analysis, co-immunoprecipitation |
Cell |
High |
18455989
|
| 1999 |
APPL1 was identified as a direct binding partner of AKT2 kinase and of the PI3K catalytic subunit p110α; APPL1 preferentially interacts with the inactive form of AKT2, suggesting it may tether inactive AKT2 to p110α in the cytoplasm. |
Yeast two-hybrid screen, co-immunoprecipitation, GST pulldown |
Oncogene |
High |
10490823
|
| 2007 |
Crystal structure of the human APPL1 N-terminal BAR-PH domain revealed a crescent-shaped symmetrical dimer with a novel linker helix integrating BAR and PH domains; biochemical analyses identified two independent Rab5-binding sites at opposite ends of the dimer where the PH domain directly contacts Rab5 and Rab21 using β-strands, a new binding mode between PH domains and small GTPases. |
X-ray crystallography, biochemical binding assays, mutagenesis |
The EMBO journal |
High |
17581628
|
| 2007 |
Crystal structures of the APPL1 BAR-PH and PTB domains revealed a novel BAR domain dimer with two four-helical bundles (unlike the three-helix bundles of other BAR domains), PH domain located at opposite ends of the BAR dimer, and confirmed that BAR, PH, and PTB domains can all bind phospholipids. |
X-ray crystallography, yeast two-hybrid, lipid binding assays |
Structure |
High |
17502098
|
| 2007 |
APPL1 mediates adiponectin-induced eNOS phosphorylation at Ser1177 and NO production in endothelial cells via AdipoR1/2; APPL1 knockdown attenuates adiponectin-induced AMPK phosphorylation and eNOS/HSP90 complex formation, while constitutively active AMPK rescues these effects. |
Proteomic analysis, RNA interference, adenoviral overexpression, co-immunoprecipitation |
Diabetes |
High |
17287464
|
| 2009 |
In muscle cells, adiponectin and metformin promote APPL1-dependent LKB1 cytosolic translocation: APPL1 directly interacts with adiponectin receptors and anchors LKB1 in the cytosol, thereby activating AMPK. A secondary pathway involving PLC/Ca2+/CaMKK also contributes. |
Co-immunoprecipitation, subcellular fractionation, siRNA knockdown, overexpression in C2C12 cells |
The Journal of biological chemistry |
High |
19520843
|
| 2009 |
APPL1 potentiates insulin-mediated suppression of hepatic gluconeogenesis by binding Akt and blocking its interaction with the endogenous inhibitor TRB3 through direct competition, thereby promoting Akt translocation to the plasma membrane and endosomes for further activation. |
Co-immunoprecipitation, competitive binding assay, APPL1 knockdown/overexpression, adenoviral gene delivery in db/db mice |
Cell metabolism |
High |
19416712
|
| 2006 |
APPL1 associates with the neurotrophin receptor TrkA through two routes: its PTB domain binds TrkA directly, and its C-terminus binds the PDZ domain of GIPC1 which also binds TrkA. APPL1, GIPC1, and phosphorylated TrkA co-fractionate in endosomal fractions. APPL1 knockdown suppresses NGF-dependent MEK, ERK, and Akt activation and neurite outgrowth. |
Mass spectrometry, co-immunoprecipitation, high-resolution centrifugation fractionation, siRNA knockdown, PC12 cell differentiation assay |
Molecular and cellular biology |
High |
17000777
|
| 2006 |
Endogenous GIPC binds the C-terminus of APPL1; upon TrkA activation by NGF, GIPC and APPL1 translocate to incoming TrkA-bearing endocytic vesicles at cell process tips. APPL1 interaction via the GIPC PDZ domain is essential for recruitment of GIPC to peripheral endosomes and for TrkA signaling (MAPK activation and neurite outgrowth); GIPC is required for efficient TrkA endocytosis and trafficking. |
Co-immunoprecipitation, siRNA knockdown, live imaging, endosome fractionation |
Molecular and cellular biology |
High |
17015470
|
| 2007 |
APPL1 forms a complex with Akt2 in primary rat adipocytes and skeletal muscle under basal conditions; this complex dissociates upon insulin stimulation. APPL1 knockdown suppresses Akt phosphorylation, glucose uptake, and GLUT4 translocation in adipocytes, and APPL1 partially co-localizes with GLUT4. |
Co-immunoprecipitation, pulldown assay, siRNA/shRNA knockdown, immunofluorescence, cellular fractionation |
The Journal of biological chemistry |
High |
17848569
|
| 2009 |
APPL2 dimerizes with APPL1 and acts as a negative regulator of adiponectin signaling in muscle cells: APPL2 overexpression inhibits APPL1-AdipoR1 interaction and suppresses downstream glucose uptake and fatty acid oxidation; adiponectin and metformin induce APPL1-APPL2 dissociation. |
Co-immunoprecipitation, RNAi, glucose uptake assay, fatty acid oxidation assay in C2C12 myotubes |
The Journal of biological chemistry |
High |
19661063
|
| 2011 |
APPL1 recruits the inositol 5-phosphatases OCRL and Inpp5B to nascent phagosomes via active Rab5; knockdown of APPL1 or inhibition of Rab5 impairs OCRL/Inpp5B association with phagosomes and prolongs PI(4,5)P2 and actin on phagosome membranes, thereby affecting Akt signaling. |
siRNA knockdown, live imaging, co-immunoprecipitation, phosphoinositide detection |
Molecular biology of the cell |
High |
22072788
|
| 2010 |
APPL1 scaffolds the TAK1-MKK3-p38 MAPK cascade in response to adiponectin: TAK1 and MKK3 bind to different regions of APPL1, and APPL1 overexpression or suppression selectively enhances or reduces adiponectin-stimulated p38 MAPK activation but not TNFα-stimulated p38 MAPK activation. |
In vitro affinity binding, co-immunoprecipitation, overexpression/siRNA in C2C12 cells |
American journal of physiology. Endocrinology and metabolism |
High |
20978232
|
| 2014 |
APPL1 forms a complex with IRS1/2 under basal conditions; upon insulin or adiponectin stimulation, this complex is recruited to the insulin receptor in a manner dependent on APPL1 phosphorylation. APPL1 deletion in mice leads to systemic insulin resistance and a selective reduction in insulin-stimulated IRS1/2 (but not IR) tyrosine phosphorylation. |
Co-immunoprecipitation, APPL1 knockout mice, phosphorylation-dependent interaction assays |
Cell reports |
High |
24813896
|
| 2009 |
APPL endosomes represent a distinct population of Rab5-positive sorting endosomes capable of sorting cargo for recycling or degradation, with long lifetimes; mathematical modeling of kinetic data rules out maturation of APPL vesicles into EEA1 endosomes as the primary mechanism, indicating APPL1 endosomes are a separate early endosomal compartment. |
Ultrastructural morphology analysis, kinetic cargo transport assays, mathematical modeling, live imaging |
The Journal of cell biology |
High |
26459602
|
| 2012 |
APPL1 potentiates insulin secretion in pancreatic β cells by enhancing Akt-dependent expression of SNARE proteins (syntaxin-1, SNAP25, VAMP2); APPL1 knockout mice show impaired glucose-stimulated insulin secretion and reduced SNARE expression, which is rescued by constitutively active Akt. |
APPL1 knockout mice, transgenic overexpression, adenoviral rescue, exocytosis measurement, western blotting |
Proceedings of the National Academy of Sciences |
High |
22566644
|
| 2009 |
APPL1 and APPL2 are novel activators of β-catenin/TCF-mediated transcription; both directly interact with the transcriptional repressor Reptin via the APPL1 PH domain, and are present in endogenous complexes containing Reptin, β-catenin, HDAC1, and HDAC2. APPL overexpression relieves Reptin-dependent repression by reducing HDAC association with Reptin. |
Reporter assay, co-immunoprecipitation, siRNA, chromatin immunoprecipitation |
The Journal of biological chemistry |
High |
19433865
|
| 2009 |
APPL1 interacts with the NuRD co-repressor complex via HDAC2 (the key NuRD subunit for this association); HDAC1 levels regulate APPL1-NuRD interactions and modulate the nucleocytoplasmic distribution of APPL1, with HDAC1 silencing promoting nuclear localization of APPL1. APPL1 also has a NuRD-independent interaction with HDAC1 and affects p21WAF1/CIP1 expression. |
Co-immunoprecipitation, siRNA, overexpression, nuclear fractionation |
The Biochemical journal |
High |
19686092
|
| 2011 |
APPL1 is required for basal NF-κB activity but not TNFα-stimulated NF-κB: APPL1 directly interacts with TRAF2 and synergizes with it to activate NF-κB upstream of the IKK complex. APPL1 increases NIK levels by reducing its association with the degradative TRAF2-TRAF3-cIAP1 complex, thereby triggering p65 nuclear translocation. |
Co-immunoprecipitation, siRNA/overexpression, gene expression profiling, luciferase reporter assay |
Journal of cell science |
High |
22685329
|
| 2011 |
APPL1 regulates adiponectin-induced LKB1 cytosolic localization through a PP2A-PKCζ signaling pathway: adiponectin promotes APPL1 interaction with PP2A and PKCζ, leading to PP2A activation, PKCζ dephosphorylation/inactivation, LKB1 dephosphorylation at Ser307, and LKB1 cytosolic translocation to activate AMPK. |
Co-immunoprecipitation, kinase/phosphatase activity assays, subcellular fractionation, siRNA in C2C12 myotubes |
Molecular endocrinology |
High |
21835890
|
| 2013 |
TRAF6 is an E3 ubiquitin ligase for APPL1; insulin induces Lys63-linked ubiquitination of APPL1 at Lys160 within the BAR domain. This ubiquitination is required for membrane localization of APPL1 and subsequent membrane recruitment and activation of Akt. A K160R mutant abolishes ubiquitination and membrane targeting, abrogating hepatic insulin sensitization. |
Co-immunoprecipitation, ubiquitination assay, site-directed mutagenesis, adenoviral gene delivery in obese mice |
The Biochemical journal |
High |
23909487
|
| 2012 |
APPL1 in postsynaptic densities associates with the NMDAR complex through binding to PSD95 at its C-terminal PDZ-binding motif; synaptic NMDAR activity increases APPL1-PI3K/Akt complex formation and promotes neuroprotective Akt activation. Disrupting the APPL1-PSD95 interaction blocks synaptic NMDAR-dependent PI3K/Akt activation and neuroprotection. |
Co-immunoprecipitation, peptide competition, lentiviral knockdown, subcellular fractionation, cell survival assay |
The Journal of neuroscience |
High |
22933778
|
| 2011 |
APPL1 localizes to dendritic spines and synapses, and regulates spine and synapse formation in hippocampal neurons. APPL1 knockdown reduces spine/synapse number; APPL1 increases active Akt in spines. The PTB domain (which binds Akt) is required, and APPL1 effects are dependent on Akt and downstream p21-activated kinase (PAK). |
siRNA knockdown, rescue with siRNA-resistant APPL1, dominant negative Akt, confocal imaging, surface AMPAR quantification |
Molecular and cellular neurosciences |
High |
21236345
|
| 2012 |
APPL1 impairs cell migration by hindering adhesion turnover at the leading edge through inhibition of Akt activity at the cell edge and within adhesions; APPL1 decreases Src-dependent tyrosine phosphorylation of Akt, which is critical for Akt-mediated migration. |
siRNA knockdown, live-cell migration assay, TIRF microscopy for adhesion dynamics, Akt activity measurement |
Molecular biology of the cell |
High |
22379109
|
| 2010 |
APPL1 proteins form homooligomers and heterooligomers via their BAR domains (necessary and sufficient for APPL-APPL interactions); all three domains (BAR, PH, PTB) target to cell membranes and bind phosphoinositides; full-length APPL-YFP recruits endogenous RAB5 to enlarged APPL-associated membrane structures. |
Co-immunoprecipitation, yeast two-hybrid, live cell imaging, phosphoinositide binding assay, FRET |
Traffic |
Medium |
18034774
|
| 2010 |
APPL1 directly interacts with FRET-confirmed homotypic (APPL1-APPL1) and heterotypic (APPL1-APPL2) BAR domain-mediated contacts on curved cell membranes in vivo. |
FRET microscopy (sensitized emission, acceptor photobleaching, sequential photobleaching) |
PloS one |
Medium |
20814572
|
| 2008 |
APPL1 interacts with OCRL (inositol 5-phosphatase mutated in Lowe syndrome); all known patient missense mutations in the ASH-RhoGAP domain of OCRL abolish APPL1 binding, and APPL1 and Rab5 independently recruit OCRL to endosomes. |
Co-immunoprecipitation, disease mutant analysis, endosome enlargement assay with constitutively active Rab5 |
Biochemical and biophysical research communications |
Medium |
18307981
|
| 2010 |
APPL1 is required for efficient Akt activation by HGF (but not EGF or insulin) in murine embryonic fibroblasts; Appl1/Appl2 double knockdown further reduces HGF-induced Akt and impairs HGF-induced cell survival and migration. |
Appl1 knockout mouse, siRNA, cell survival and migration assays, growth factor stimulation |
The Journal of biological chemistry |
Medium |
20040596
|
| 2015 |
APPL1 mediates βCTF (β-cleaved C-terminal fragment of APP)-induced Rab5 overactivation in Alzheimer's disease and Down syndrome: βCTF recruits APPL1 to Rab5 endosomes where it stabilizes GTP-bound Rab5, leading to accelerated endocytosis, endosome swelling, and impaired axonal transport of Rab5 endosomes. APPL1 knockdown corrects these endosomal anomalies in Down syndrome fibroblasts. |
Co-immunoprecipitation, siRNA knockdown, live imaging, endosome morphometry, axonal transport assay |
Molecular psychiatry |
High |
26194181
|
| 2017 |
APPL1 is required for rapid recycling of LHR (luteinizing hormone receptor) from very early endosomes (VEEs) and for endosomal cAMP signaling; LHR recycling is driven by Gαs/cAMP signaling from the VEE and PKA-dependent phosphorylation of APPL1 at serine 410. |
siRNA knockdown, FRET-based cAMP biosensor, receptor recycling assay, phosphorylation mapping |
Cell reports |
High |
29212031
|
| 2019 |
APPL1-positive endosomes in hippocampal axons exhibit predominantly retrograde motility; APPL1 endosomes transport TrkB and mediate retrograde axonal transport of Akt1. FRET analysis confirmed that APPL1 and Akt1 interact in an endocytosis-dependent manner. |
Live-cell imaging of primary mouse hippocampal neurons, FRET analysis, endosome tracking |
Scientific reports |
High |
30792402
|
| 2019 |
Dynamin-1 (Dyn1), upregulated by gain-of-function mutant p53, recruits and stabilizes APPL1 on peripheral endosomes; these APPL1 endosomes modulate Akt signaling and activate Dyn1 in a positive feedback loop that promotes rapid recycling of EGFR and β1 integrins, focal adhesion turnover, and cell migration. |
siRNA knockdown, live imaging quantification of peripheral endosomes, integrin recycling assay, focal adhesion dynamics |
The Journal of cell biology |
High |
31043431
|
| 2012 |
APPL1 is required for TLR3/4-dependent IRF3 activation; TBK1 and IKKε are recruited to APPL1 endosomes in LPS-stimulated macrophages. APPL1 undergoes proteasome-mediated degradation through ERK1/2 to terminate signaling, and this degradation is blocked when endosomal signaling is inhibited. |
siRNA knockdown, co-immunoprecipitation, proteasome inhibitors, chloroquine/dynasore treatment, IRF3 target gene expression |
Journal of immunology |
High |
25780039
|
| 2016 |
APPL1 and APPL2 are required for TGFβ-induced nuclear translocation of the TGFβ type I receptor intracellular domain (TβRI-ICD) and for cancer cell invasiveness; APPL proteins associate with TβRI in a TRAF6-dependent manner. |
siRNA knockdown, co-immunoprecipitation, nuclear fractionation, invasion assay |
Oncotarget |
Medium |
26583432
|
| 2012 |
APPL1 deficiency in β cells impairs glucose-stimulated insulin secretion by reducing mitochondrial function (oxygen consumption rate, ATP production, mitochondrial membrane potential) and expression of mitochondrial biogenesis genes. |
APPL1 knockout mice, hyperglycemic clamp, siRNA/overexpression in INS-1 cells, mitochondrial function assays |
Diabetologia |
High |
23793716
|
| 2012 |
APPL1 phosphorylation at Ser430 by PKCα mediates ER stress-induced insulin resistance in hepatocytes: ER stress or PKCα activation increases APPL1 Ser430 phosphorylation; phosphomimetic APPL1(S430D) impairs Akt Thr308 phosphorylation, whereas APPL1(S430A) does not. |
Site-directed mutagenesis, siRNA, kinase assay, western blotting in mouse hepatocytes |
The Journal of biological chemistry |
High |
22685300
|
| 2015 |
Two APPL1 loss-of-function mutations (p.Leu552* and p.Asp94Asn) in familial diabetes: Leu552* abolishes protein expression, while Asp94Asn significantly reduces APPL1-enhanced insulin-stimulated AKT2 and GSK3β phosphorylation, confirming that APPL1 enhances insulin-induced AKT2 activation in a physiologically relevant manner. |
Whole-exome sequencing, transfection in HepG2 cells, AKT2/GSK3β phosphorylation assay |
American journal of human genetics |
High |
26073777
|
| 2011 |
Annexin A2 interacts with both APPL1 and APPL2 and co-fractionates with APPL endosomes; silencing Annexin A2 causes solubilization of APPL2 from endosomes, indicating it plays an important role in membrane recruitment of APPL proteins acting in parallel to Rab5. |
Co-immunoprecipitation, membrane fractionation, density gradients, siRNA knockdown |
Traffic |
Medium |
21645192
|
| 2016 |
Serine 707 of APPL1 within its C-terminal PDZ-binding motif is a critical phosphorylation site for binding to the PDZ2 domain of PSD95 and for activation of the Akt signaling pathway during synaptic NMDAR activity. |
Co-immunoprecipitation, mutagenesis, western blotting in rat cortical neurons |
Neuroscience bulletin |
Medium |
27300007
|
| 2021 |
APPL1 is required for early endosome-dependent mitophagy in macrophages: upon NLRP3 agonist stimulation, APPL1 translocates from early endosomes to mitochondria where it interacts with Rab5 to facilitate endosomal-mediated mitophagy, restricting NLRP3 inflammasome overactivation. APPL1-deficient macrophages accumulate damaged mitochondria producing ROS and oxidized mtDNA. |
APPL1 knockout mice (hematopoietic-specific), co-immunoprecipitation, mitophagy assay, NLRP3 inflammasome activation assay, live imaging |
Nature communications |
High |
34789781
|
| 2011 |
APPL1 counteracts obesity-induced vascular insulin resistance by modulating the balance between Akt-dependent NO production and ERK1/2-mediated ET-1 secretion in endothelium: APPL1 competes with TRB3 to potentiate Akt activation, and alters Raf-1 phosphorylation to suppress ERK1/2 signaling. APPL1 KO mice show shifted insulin response from vasodilation to vasoconstriction. |
APPL1 KO and transgenic mice, vascular reactivity assay, co-immunoprecipitation, endothelial cell signaling analysis |
Diabetes |
High |
21926268
|
| 2004 |
APPL1 coimmunoprecipitates with FSH receptor (FSHR) in HEK 293 cells; FSHR co-immunoprecipitates with Akt; FSH treatment induces FOXO1a phosphorylation linking FSHR-APPL1 interaction to the PI3K/Akt pathway. |
Yeast two-hybrid, co-immunoprecipitation, FSH stimulation assay |
Biology of reproduction |
Medium |
15070827
|
| 2011 |
APPL1 links FSHR to inositol 1,4,5-trisphosphate production and intracellular Ca2+ mobilization: mutation of FSHR-K376A abolishes APPL1 association without affecting FSH binding or cAMP production, but curtails IP3 production and Ca2+ mobilization from intracellular stores. |
Alanine scanning mutagenesis, co-immunoprecipitation, IP3 assay, Ca2+ imaging |
Endocrinology |
High |
21285318
|
| 2003 |
APPL1 suppresses androgen receptor (AR) transactivation in a dose-dependent manner dependent on the PI3K/Akt pathway; APPL1 enhances IGF-1-mediated Akt activation; co-immunoprecipitation and GST pulldown show APPL1, Akt, and AR may exist in a complex with Akt bridging APPL1-AR association. |
Reporter gene assay, Northern blot, co-immunoprecipitation, GST pulldown, dominant negative constructs |
The Journal of biological chemistry |
Medium |
12621049
|
| 2020 |
Membrane progesterone receptor β (mPRβ) signals through clathrin-dependent endocytosis into signaling endosomes where it transiently interacts with APPL1 and Akt2; APPL1 is required for mPRβ-mediated induction of Xenopus oocyte meiosis downstream of endocytosis. |
Xenopus oocyte meiosis assay, siRNA/morpholino knockdown, co-immunoprecipitation, endocytosis inhibition |
PLoS biology |
High |
33137110
|
| 2016 |
APPL1 directly binds to both leptin receptor and STAT3; leptin stimulation enhances this interaction in a time-dependent manner and increases APPL1 phosphorylation; APPL1 overexpression or knockdown promotes or attenuates leptin-induced STAT3, ERK1/2, and Akt phosphorylation and cancer cell proliferation/migration. |
Co-immunoprecipitation, siRNA knockdown, overexpression, migration/proliferation assays |
PloS one |
Medium |
27820851
|
| 2014 |
APPL1 and APPL2 interact with ATM after irradiation and are required for DNA double-strand break repair and ATM hyperphosphorylation; APPL knockdown reduces radiation survival in pancreatic carcinoma cells, and double targeting of APPL and ATM causes additive radiosensitization, suggesting APPL acts upstream of or directly on ATM. |
Co-immunoprecipitation, siRNA knockdown, clonogenic survival assay, γH2AX DSB repair assay |
Cell death & disease |
Medium |
24763056
|
| 2016 |
APPL1 deficiency in β cells potentiates cytokine-induced NFκB activation (IκBα and p65 phosphorylation), leading to increased apoptotic and proinflammatory gene expression including iNOS; pharmacological NFκB or iNOS inhibition largely abrogates the detrimental effects of APPL1 deficiency. |
APPL1 KO mice, AAV overexpression, streptozotocin diabetes model, siRNA, phosphorylation assay |
Diabetologia |
High |
28011992
|
| 2010 |
Cdo (a promyogenic cell surface protein) forms a complex with APPL1 and Boc in differentiating myoblasts; both Cdo and APPL1 are required for efficient Akt activation during myoblast differentiation, and constitutively active Akt rescues Cdo-depleted cell differentiation defects. |
Co-immunoprecipitation, siRNA knockdown, differentiation assay, constitutively active Akt rescue |
Molecular biology of the cell |
Medium |
20484574
|