{"gene":"KANK2","run_date":"2026-06-10T01:55:23","timeline":{"discoveries":[{"year":2016,"finding":"KANK2 (and other Kank family members) accumulate at the lateral border of focal adhesions (FA belt) and in central sliding adhesions, where they directly bind the talin rod domain through the Kank amino-terminal (KN) motif, inducing talin and integrin activation while diminishing the talin-actomyosin linkage, thereby reducing force transmission across integrins and promoting central adhesion formation and sliding.","method":"Co-IP/pulldown identifying KN motif–talin rod interaction, FRET-based tension sensors across integrins, live-cell imaging of adhesion dynamics, mutagenesis of KN motif","journal":"Nature cell biology","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — direct binding domain mapping (KN motif), force-sensor measurements, live imaging, and functional rescue experiments across multiple cell types in a single rigorous study","pmids":["27548916"],"is_preprint":false},{"year":2014,"finding":"KANK2 (SIP) sequesters steroid receptor coactivators (SRC-2 and SRC-3) in the cytoplasm; a missense mutation (p.Ala670Val) abolishes this sequestering activity, causing SRC-2 and SRC-3 to mislocalize to the nucleus of epidermal basal cells, increasing vitamin D receptor-driven transactivation in patient keratinocytes.","method":"Immunofluorescence localization of SRC-2/SRC-3 in patient vs. control keratinocytes; vitamin D-induced transactivation assays in patient cells; whole-exome sequencing identifying causative mutation","journal":"Journal of medical genetics","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — cellular localization and functional transactivation assays in patient-derived cells with a defined mutation, single lab, two orthogonal readouts","pmids":["24671081"],"is_preprint":false},{"year":2017,"finding":"The C-terminal ankyrin repeat domain of KANK2 directly binds a ~22 amino acid stretch of KIF21A, adopting a helical conformation at two distinct pockets of the ankyrin domain, as revealed by crystal structures of the KANK2 ankyrin domain–KIF21A peptide complex, validated by site-directed mutagenesis.","method":"Crystal structure determination, site-directed mutagenesis, biochemical binding assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure plus mutagenesis and in vitro biochemical validation in a single rigorous study","pmids":["29183992"],"is_preprint":false},{"year":2020,"finding":"KANK2 is a key component of integrin αVβ5 integrin adhesion complexes linking them to microtubules via the cortical microtubule stabilization complex (CMSC); KANK2 knockdown mimics integrin αV knockdown by increasing sensitivity to microtubule poisons (paclitaxel, vincristine) and decreasing cell migration.","method":"Mass spectrometry-based proteomics of isolated integrin adhesion complexes; siRNA knockdown with drug sensitivity and migration assays","journal":"Frontiers in cell and developmental biology","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — MS proteomics of adhesion complexes plus functional siRNA knockdown phenotyping, single lab, two orthogonal methods","pmids":["32195252"],"is_preprint":false},{"year":2021,"finding":"An NS-associated KANK2 mutation (S684F) creates a gain-of-binding interaction with eIF4A1 at the same site used by KIF21A; eIF4A1 competitively displaces KIF21A from the S684F mutant, and the mutant fails to rescue focal adhesion structure or cell adhesion in KANK2-knockout podocytes, converting a gain-of-binding mutation into a functional loss-of-function.","method":"Crystal structure of KANK2(S684F)–eIF4A1 complex; competitive binding assays; KANK2 knockout in mouse podocytes with rescue experiments; immunofluorescence of focal adhesions","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — structural determination plus competitive biochemical assay plus cellular rescue experiment in a single study, single lab","pmids":["34274317"],"is_preprint":false},{"year":2022,"finding":"HSP70 physically interacts with KANK2; this interaction reduces AIF release and apoptosis in lung epithelial cells; KANK2 knockdown in epithelial cells aggravates apoptosis and tissue damage, while HSP70 treatment reverses cell death in a KANK2-dependent manner.","method":"Co-immunoprecipitation of HSP70–KANK2 complex; siRNA knockdown of KANK2; hsp70.1 gene deletion in CLP mice; TUNEL staining; AIF release assay","journal":"Biomolecules","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — reciprocal Co-IP and genetic loss-of-function in two model systems (cells and mice), single lab","pmids":["35327602"],"is_preprint":false},{"year":2023,"finding":"In MDA-MB-435S melanoma cells (which rely on integrin αVβ5), KANK2 specifically interacts with talin2 (not talin1) within focal adhesions; talin2 knockdown phenocopies KANK2 knockdown, perturbing actin–MT crosstalk (increased MT growth velocity), increasing paclitaxel sensitivity, and reducing cell migration, whereas KANK1 knockdown has none of these effects.","method":"siRNA knockdown of talin1, talin2, KANK1, or KANK2; live-cell imaging of MT dynamics; paclitaxel sensitivity assay; Transwell migration assay; Western blot of isolated integrin adhesion complexes","journal":"Cellular & molecular biology letters","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — multiple siRNA conditions with orthogonal functional readouts (MT dynamics, drug sensitivity, migration), single lab","pmids":["37460977"],"is_preprint":false},{"year":2010,"finding":"KANK2 (ankrd25) protein is localized to podocyte foot processes in mouse kidney, as determined by immunohistochemistry with a polyclonal antibody.","method":"Immunohistochemistry; RT-PCR for tissue expression","journal":"Nephron. Experimental nephrology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single localization method (IHC) with no functional consequence established","pmids":["20720434"],"is_preprint":false},{"year":2024,"finding":"Transcription factors E2F1, TFAP2C, and NRF1 bind the upstream promoter of KANK2 to transactivate its expression in renal tubular epithelial cells; knockdown of any of these factors reduces KANK2 expression, deforms the actin cytoskeleton, and decreases F-actin content.","method":"EMSA and ChIP assays for transcription factor binding; siRNA knockdown of transcription factors with F-actin and cytoskeleton readouts; promoter mapping","journal":"Experimental cell research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — EMSA and ChIP provide direct evidence of TF binding, complemented by siRNA functional readouts, single lab","pmids":["38253280"],"is_preprint":false},{"year":2026,"finding":"In RPMI-7951 melanoma cells, KANK2 is present in both integrin αVβ5 focal adhesions (FAs) and integrin α5β1 fibrillar adhesions (FBs); at FAs it functionally interacts with talin1 to maintain FA integrity and with talin2 to regulate FA dynamics; at FBs, KANK2 knockdown mimics integrin α5 knockdown by increasing microtubule-dependent cell migration, indicating KANK2 links FBs to microtubules and stabilizes them.","method":"siRNA knockdown; mass spectrometry of isolated integrin adhesion complexes; proximity ligation assay; live-cell imaging; Transwell migration assay; paclitaxel sensitivity assay","journal":"Cell communication and signaling : CCS","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — proximity ligation assays, MS proteomics, and functional siRNA phenotyping with multiple orthogonal readouts, single lab","pmids":["41776630"],"is_preprint":false}],"current_model":"KANK2 is a scaffold protein that localizes to the lateral border of focal adhesions and to fibrillar adhesions, where its KN motif directly binds the talin rod domain (preferentially talin2 in αVβ5-dominant cells, talin1 or talin2 in mixed-adhesion contexts) to activate talin/integrins while uncoupling the talin–actomyosin linkage, thereby reducing integrin tension and modulating cell migration speed; its C-terminal ankyrin repeat domain recruits KIF21A and links adhesions to the cortical microtubule stabilization complex to control microtubule dynamics, and a disease-causing mutation (S684F) pathologically redirects this binding site to eIF4A1, competitively displacing KIF21A and causing podocyte dysfunction; additionally, KANK2 sequesters steroid receptor coactivators (SRC-2/3) in the cytoplasm to limit VDR-driven transcription, and physically interacts with HSP70 to suppress AIF-mediated apoptosis."},"narrative":{"mechanistic_narrative":"KANK2 is a scaffold protein of integrin adhesion complexes that couples adhesions to the microtubule cytoskeleton and tunes the mechanical link between integrins and actomyosin [PMID:27548916, PMID:32195252]. It accumulates at the lateral border of focal adhesions and in central sliding adhesions, where its N-terminal KN motif directly binds the talin rod domain to activate talin and integrins while diminishing the talin–actomyosin linkage, thereby lowering force transmission across integrins and promoting central adhesion sliding [PMID:27548916]. Its C-terminal ankyrin repeat domain directly engages a short helical KIF21A peptide at two distinct pockets, as resolved by crystallography, recruiting the cortical microtubule stabilization complex to adhesions and controlling microtubule dynamics and cell migration [PMID:29183992, PMID:32195252]. In integrin αVβ5-dependent cells KANK2 acts preferentially through talin2 to regulate actin–microtubule crosstalk and drug sensitivity, while in mixed-adhesion contexts it engages talin1 for focal adhesion integrity and talin2 for dynamics and additionally links α5β1 fibrillar adhesions to stabilized microtubules [PMID:37460977, PMID:41776630]. A nephrotic-syndrome–associated mutation (S684F) creates a gain-of-binding site for eIF4A1 that competitively displaces KIF21A and abolishes the ability of KANK2 to rescue focal adhesion structure in knockout podocytes, converting a gain of binding into functional loss [PMID:34274317]. Independent of its adhesion role, KANK2 sequesters steroid receptor coactivators SRC-2 and SRC-3 in the cytoplasm to limit vitamin D receptor–driven transactivation [PMID:24671081], and physically interacts with HSP70 to reduce AIF release and apoptosis in epithelial cells [PMID:35327602].","teleology":[{"year":2014,"claim":"Established a first molecular function for KANK2 by showing it retains transcriptional coactivators in the cytoplasm, with a disease mutation releasing them to the nucleus.","evidence":"Immunofluorescence of SRC-2/SRC-3 and vitamin D transactivation assays in patient vs. control keratinocytes, plus exome sequencing of the causative p.Ala670Val mutation","pmids":["24671081"],"confidence":"Medium","gaps":["Direct physical SRC-2/3–KANK2 binding interface not mapped","Connection to the adhesion/microtubule role of KANK2 unestablished","Single patient lineage"]},{"year":2016,"claim":"Defined the core adhesion mechanism: KANK2 binds the talin rod via its KN motif to activate integrins while uncoupling talin from actomyosin, reducing integrin tension.","evidence":"Co-IP/pulldown mapping the KN motif–talin rod interaction, FRET integrin tension sensors, live-cell imaging and KN-motif mutagenesis across cell types","pmids":["27548916"],"confidence":"High","gaps":["Talin isoform preference not resolved in this study","Quantitative contribution to migration left for later work"]},{"year":2017,"claim":"Resolved the structural basis for microtubule coupling, showing how the KANK2 ankyrin domain captures a KIF21A peptide at two pockets.","evidence":"Crystal structures of the KANK2 ankyrin domain–KIF21A peptide complex with site-directed mutagenesis and biochemical binding assays","pmids":["29183992"],"confidence":"High","gaps":["Cellular consequences of disrupting the interface not tested here","Whether the two pockets bind cooperatively unaddressed"]},{"year":2020,"claim":"Placed KANK2 functionally within αVβ5 integrin adhesion complexes as the link to microtubules controlling drug sensitivity and migration.","evidence":"Mass spectrometry of isolated integrin adhesion complexes and siRNA knockdown with paclitaxel/vincristine sensitivity and migration assays","pmids":["32195252"],"confidence":"Medium","gaps":["Talin isoform mediating the link not identified","Mechanism connecting microtubule stabilization to drug sensitivity unresolved"]},{"year":2021,"claim":"Explained how a nephrotic-syndrome mutation acts: S684F gains an eIF4A1-binding site that competitively displaces KIF21A, producing functional loss of adhesion rescue.","evidence":"Crystal structure of KANK2(S684F)–eIF4A1, competitive binding assays, and rescue experiments in KANK2-knockout mouse podocytes","pmids":["34274317"],"confidence":"High","gaps":["Physiological role, if any, of eIF4A1 in wild-type podocytes unclear","In vivo kidney phenotype of the mutation not established in this study"]},{"year":2022,"claim":"Identified an anti-apoptotic role through HSP70, distinct from adhesion signaling.","evidence":"Reciprocal Co-IP of HSP70–KANK2, siRNA knockdown, hsp70.1 deletion in CLP mice, TUNEL staining and AIF release assays","pmids":["35327602"],"confidence":"Medium","gaps":["KANK2 domain mediating HSP70 binding not mapped","Mechanistic link between KANK2 and AIF retention unresolved"]},{"year":2023,"claim":"Demonstrated talin isoform specificity, showing KANK2 acts through talin2 in αVβ5-reliant melanoma cells where KANK1 is dispensable.","evidence":"Talin1/talin2/KANK1/KANK2 siRNA, live-cell MT dynamics imaging, paclitaxel sensitivity and Transwell migration assays with adhesion-complex Western blots","pmids":["37460977"],"confidence":"Medium","gaps":["Generality across non-αVβ5 cell types untested in this study","Direct talin2 binding interface not re-mapped"]},{"year":2024,"claim":"Identified upstream transcriptional control of KANK2 expression governing actin cytoskeleton integrity.","evidence":"EMSA and ChIP for E2F1, TFAP2C and NRF1 binding to the KANK2 promoter plus siRNA knockdown with F-actin readouts in renal tubular epithelial cells","pmids":["38253280"],"confidence":"Medium","gaps":["Signals regulating these transcription factors on KANK2 unknown","Direct vs. indirect cytoskeletal effects of TF knockdown not separated"]},{"year":2026,"claim":"Extended the model to fibrillar adhesions and dual talin engagement, showing KANK2 links both αVβ5 focal adhesions and α5β1 fibrillar adhesions to stabilized microtubules.","evidence":"siRNA knockdown, MS of isolated adhesion complexes, proximity ligation assays, live-cell imaging, migration and paclitaxel sensitivity assays in RPMI-7951 cells","pmids":["41776630"],"confidence":"Medium","gaps":["Structural basis for talin1 vs. talin2 selectivity not resolved","How a single KN motif partitions between adhesion types unknown"]},{"year":null,"claim":"How KANK2's distinct activities—talin/integrin scaffolding, coactivator sequestration, and HSP70/AIF-dependent apoptosis suppression—are integrated within a single cell remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unifying study connecting the adhesion and non-adhesion roles","Regulation governing which interaction dominates in a given context unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,2,3]},{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[0,3]},{"term_id":"GO:0140313","term_label":"molecular sequestering activity","supporting_discovery_ids":[1]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,3,9]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[1]}],"pathway":[{"term_id":"R-HSA-1474244","term_label":"Extracellular matrix organization","supporting_discovery_ids":[0,3,9]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0]}],"complexes":["cortical microtubule stabilization complex (CMSC)","integrin αVβ5 adhesion complex"],"partners":["TLN1","TLN2","KIF21A","EIF4A1","HSPA1A","NCOA2","NCOA3"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q63ZY3","full_name":"KN motif and ankyrin repeat domain-containing protein 2","aliases":["Ankyrin repeat domain-containing protein 25","Matrix-remodeling-associated protein 3","SRC-1-interacting protein","SIP","SRC-interacting protein","SRC1-interacting protein"],"length_aa":851,"mass_kda":91.2,"function":"Involved in transcription regulation by sequestering in the cytoplasm nuclear receptor coactivators such as NCOA1, NCOA2 and NCOA3 (PubMed:17476305). Involved in regulation of caspase-independent apoptosis by sequestering the proapoptotic factor AIFM1 in mitochondria (PubMed:22371500). Pro-apoptotic stimuli can induce its proteasomal degradation allowing the translocation of AIFM1 to the nucleus to induce apoptosis (PubMed:22371500). Involved in the negative control of vitamin D receptor signaling pathway (PubMed:24671081). Involved in actin stress fibers formation through its interaction with ARHGDIA and the regulation of the Rho signaling pathway (PubMed:17996375, PubMed:25961457). May thereby play a role in cell adhesion and migration, regulating for instance podocytes migration during development of the kidney (PubMed:25961457). Through the Rho signaling pathway may also regulate cell proliferation (By similarity)","subcellular_location":"Cytoplasm; Mitochondrion","url":"https://www.uniprot.org/uniprotkb/Q63ZY3/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/KANK2","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"DYNLL1","stoichiometry":0.2},{"gene":"DYNLL2","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/KANK2","total_profiled":1310},"omim":[{"mim_id":"617783","title":"NEPHROTIC SYNDROME, TYPE 16; NPHS16","url":"https://www.omim.org/entry/617783"},{"mim_id":"616099","title":"PALMOPLANTAR KERATODERMA AND WOOLLY HAIR; PPKWH","url":"https://www.omim.org/entry/616099"},{"mim_id":"614612","title":"KN MOTIF- AND ANKYRIN REPEAT DOMAIN-CONTAINING PROTEIN 4; KANK4","url":"https://www.omim.org/entry/614612"},{"mim_id":"614611","title":"KN MOTIF- AND ANKYRIN REPEAT DOMAIN-CONTAINING PROTEIN 3; KANK3","url":"https://www.omim.org/entry/614611"},{"mim_id":"614610","title":"KN MOTIF- AND ANKYRIN REPEAT DOMAIN-CONTAINING PROTEIN 2; KANK2","url":"https://www.omim.org/entry/614610"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nucleoplasm","reliability":"Approved"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/KANK2"},"hgnc":{"alias_symbol":["KIAA1518","SIP"],"prev_symbol":["MXRA3","ANKRD25"]},"alphafold":{"accession":"Q63ZY3","domains":[{"cath_id":"1.25.40.20","chopping":"591-694","consensus_level":"medium","plddt":94.1645,"start":591,"end":694},{"cath_id":"1.25.40.20","chopping":"699-835","consensus_level":"medium","plddt":94.2904,"start":699,"end":835}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q63ZY3","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q63ZY3-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q63ZY3-F1-predicted_aligned_error_v6.png","plddt_mean":60.09},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=KANK2","jax_strain_url":"https://www.jax.org/strain/search?query=KANK2"},"sequence":{"accession":"Q63ZY3","fasta_url":"https://rest.uniprot.org/uniprotkb/Q63ZY3.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q63ZY3/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q63ZY3"}},"corpus_meta":[{"pmid":"27548916","id":"PMC_27548916","title":"Kank2 activates talin, reduces force transduction across integrins and induces central adhesion formation.","date":"2016","source":"Nature cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/27548916","citation_count":133,"is_preprint":false},{"pmid":"24671081","id":"PMC_24671081","title":"Mutation in KANK2, encoding a sequestering protein for steroid receptor coactivators, causes keratoderma and woolly hair.","date":"2014","source":"Journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/24671081","citation_count":33,"is_preprint":false},{"pmid":"32195252","id":"PMC_32195252","title":"KANK2 Links αVβ5 Focal Adhesions to Microtubules and Regulates Sensitivity to Microtubule Poisons and Cell Migration.","date":"2020","source":"Frontiers in cell and developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/32195252","citation_count":28,"is_preprint":false},{"pmid":"35327602","id":"PMC_35327602","title":"HSP70 Ameliorates Septic Lung Injury via Inhibition of Apoptosis by Interacting with KANK2.","date":"2022","source":"Biomolecules","url":"https://pubmed.ncbi.nlm.nih.gov/35327602","citation_count":26,"is_preprint":false},{"pmid":"37460977","id":"PMC_37460977","title":"Talin2 and KANK2 functionally interact to regulate microtubule dynamics, paclitaxel sensitivity and cell migration in the MDA-MB-435S melanoma cell line.","date":"2023","source":"Cellular & molecular biology letters","url":"https://pubmed.ncbi.nlm.nih.gov/37460977","citation_count":15,"is_preprint":false},{"pmid":"29183992","id":"PMC_29183992","title":"Structural basis for the recognition of kinesin family member 21A (KIF21A) by the ankyrin domains of KANK1 and KANK2 proteins.","date":"2017","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/29183992","citation_count":15,"is_preprint":false},{"pmid":"37919278","id":"PMC_37919278","title":"Cross species systems biology discovers glial DDR2, STOM, and KANK2 as therapeutic targets in progressive supranuclear palsy.","date":"2023","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/37919278","citation_count":13,"is_preprint":false},{"pmid":"32570033","id":"PMC_32570033","title":"Therapeutic effects of KANK2 in myocardial infarction rats might be associated with the NF-κB p65 inhibition.","date":"2020","source":"International immunopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/32570033","citation_count":9,"is_preprint":false},{"pmid":"34274317","id":"PMC_34274317","title":"Nephrotic-syndrome-associated mutation of KANK2 induces pathologic binding competition with physiological interactor KIF21A.","date":"2021","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/34274317","citation_count":5,"is_preprint":false},{"pmid":"20720434","id":"PMC_20720434","title":"Expression of novel podocyte-associated proteins sult1b1 and ankrd25.","date":"2010","source":"Nephron. Experimental nephrology","url":"https://pubmed.ncbi.nlm.nih.gov/20720434","citation_count":2,"is_preprint":false},{"pmid":"39895803","id":"PMC_39895803","title":"Pan-Cancer Analysis of KANK2: Clinical and Molecular Insights into Tumor Progression and Therapeutic Implications.","date":"2025","source":"Journal of Cancer","url":"https://pubmed.ncbi.nlm.nih.gov/39895803","citation_count":2,"is_preprint":false},{"pmid":"38253280","id":"PMC_38253280","title":"Transcriptional mechanism of E2F1/TFAP2C/NRF1 in regulating KANK2 gene in nephrotic syndrome.","date":"2024","source":"Experimental cell research","url":"https://pubmed.ncbi.nlm.nih.gov/38253280","citation_count":1,"is_preprint":false},{"pmid":"42032724","id":"PMC_42032724","title":"Regulation of reticular adhesions by KANK2 and talin2 in two melanoma cell lines.","date":"2026","source":"Cell communication and signaling : CCS","url":"https://pubmed.ncbi.nlm.nih.gov/42032724","citation_count":0,"is_preprint":false},{"pmid":"41776630","id":"PMC_41776630","title":"KANK2 at focal adhesions regulates their maintenance and dynamics, while at fibrillar adhesions it influences cell migration via microtubule-dependent mechanism.","date":"2026","source":"Cell communication and signaling : CCS","url":"https://pubmed.ncbi.nlm.nih.gov/41776630","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.02.24.639831","title":"KANK2 at focal adhesion regulates their maintenance and dynamics, while at fibrillar adhesions it influences cell migration via microtubule-dependent mechanism","date":"2025-02-26","source":"bioRxiv","url":"https://doi.org/10.1101/2025.02.24.639831","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":9691,"output_tokens":2722,"usd":0.034952,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":10050,"output_tokens":3530,"usd":0.06925,"stage2_stop_reason":"end_turn"},"total_usd":0.104202,"stage1_batch_id":"msgbatch_01DUPACZi7AAWwuZiUjseQF4","stage2_batch_id":"msgbatch_018yt7chE3f48PEFtDwtj6AE","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2016,\n      \"finding\": \"KANK2 (and other Kank family members) accumulate at the lateral border of focal adhesions (FA belt) and in central sliding adhesions, where they directly bind the talin rod domain through the Kank amino-terminal (KN) motif, inducing talin and integrin activation while diminishing the talin-actomyosin linkage, thereby reducing force transmission across integrins and promoting central adhesion formation and sliding.\",\n      \"method\": \"Co-IP/pulldown identifying KN motif–talin rod interaction, FRET-based tension sensors across integrins, live-cell imaging of adhesion dynamics, mutagenesis of KN motif\",\n      \"journal\": \"Nature cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — direct binding domain mapping (KN motif), force-sensor measurements, live imaging, and functional rescue experiments across multiple cell types in a single rigorous study\",\n      \"pmids\": [\"27548916\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"KANK2 (SIP) sequesters steroid receptor coactivators (SRC-2 and SRC-3) in the cytoplasm; a missense mutation (p.Ala670Val) abolishes this sequestering activity, causing SRC-2 and SRC-3 to mislocalize to the nucleus of epidermal basal cells, increasing vitamin D receptor-driven transactivation in patient keratinocytes.\",\n      \"method\": \"Immunofluorescence localization of SRC-2/SRC-3 in patient vs. control keratinocytes; vitamin D-induced transactivation assays in patient cells; whole-exome sequencing identifying causative mutation\",\n      \"journal\": \"Journal of medical genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — cellular localization and functional transactivation assays in patient-derived cells with a defined mutation, single lab, two orthogonal readouts\",\n      \"pmids\": [\"24671081\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"The C-terminal ankyrin repeat domain of KANK2 directly binds a ~22 amino acid stretch of KIF21A, adopting a helical conformation at two distinct pockets of the ankyrin domain, as revealed by crystal structures of the KANK2 ankyrin domain–KIF21A peptide complex, validated by site-directed mutagenesis.\",\n      \"method\": \"Crystal structure determination, site-directed mutagenesis, biochemical binding assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure plus mutagenesis and in vitro biochemical validation in a single rigorous study\",\n      \"pmids\": [\"29183992\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"KANK2 is a key component of integrin αVβ5 integrin adhesion complexes linking them to microtubules via the cortical microtubule stabilization complex (CMSC); KANK2 knockdown mimics integrin αV knockdown by increasing sensitivity to microtubule poisons (paclitaxel, vincristine) and decreasing cell migration.\",\n      \"method\": \"Mass spectrometry-based proteomics of isolated integrin adhesion complexes; siRNA knockdown with drug sensitivity and migration assays\",\n      \"journal\": \"Frontiers in cell and developmental biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — MS proteomics of adhesion complexes plus functional siRNA knockdown phenotyping, single lab, two orthogonal methods\",\n      \"pmids\": [\"32195252\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"An NS-associated KANK2 mutation (S684F) creates a gain-of-binding interaction with eIF4A1 at the same site used by KIF21A; eIF4A1 competitively displaces KIF21A from the S684F mutant, and the mutant fails to rescue focal adhesion structure or cell adhesion in KANK2-knockout podocytes, converting a gain-of-binding mutation into a functional loss-of-function.\",\n      \"method\": \"Crystal structure of KANK2(S684F)–eIF4A1 complex; competitive binding assays; KANK2 knockout in mouse podocytes with rescue experiments; immunofluorescence of focal adhesions\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — structural determination plus competitive biochemical assay plus cellular rescue experiment in a single study, single lab\",\n      \"pmids\": [\"34274317\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"HSP70 physically interacts with KANK2; this interaction reduces AIF release and apoptosis in lung epithelial cells; KANK2 knockdown in epithelial cells aggravates apoptosis and tissue damage, while HSP70 treatment reverses cell death in a KANK2-dependent manner.\",\n      \"method\": \"Co-immunoprecipitation of HSP70–KANK2 complex; siRNA knockdown of KANK2; hsp70.1 gene deletion in CLP mice; TUNEL staining; AIF release assay\",\n      \"journal\": \"Biomolecules\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — reciprocal Co-IP and genetic loss-of-function in two model systems (cells and mice), single lab\",\n      \"pmids\": [\"35327602\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"In MDA-MB-435S melanoma cells (which rely on integrin αVβ5), KANK2 specifically interacts with talin2 (not talin1) within focal adhesions; talin2 knockdown phenocopies KANK2 knockdown, perturbing actin–MT crosstalk (increased MT growth velocity), increasing paclitaxel sensitivity, and reducing cell migration, whereas KANK1 knockdown has none of these effects.\",\n      \"method\": \"siRNA knockdown of talin1, talin2, KANK1, or KANK2; live-cell imaging of MT dynamics; paclitaxel sensitivity assay; Transwell migration assay; Western blot of isolated integrin adhesion complexes\",\n      \"journal\": \"Cellular & molecular biology letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — multiple siRNA conditions with orthogonal functional readouts (MT dynamics, drug sensitivity, migration), single lab\",\n      \"pmids\": [\"37460977\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"KANK2 (ankrd25) protein is localized to podocyte foot processes in mouse kidney, as determined by immunohistochemistry with a polyclonal antibody.\",\n      \"method\": \"Immunohistochemistry; RT-PCR for tissue expression\",\n      \"journal\": \"Nephron. Experimental nephrology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single localization method (IHC) with no functional consequence established\",\n      \"pmids\": [\"20720434\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Transcription factors E2F1, TFAP2C, and NRF1 bind the upstream promoter of KANK2 to transactivate its expression in renal tubular epithelial cells; knockdown of any of these factors reduces KANK2 expression, deforms the actin cytoskeleton, and decreases F-actin content.\",\n      \"method\": \"EMSA and ChIP assays for transcription factor binding; siRNA knockdown of transcription factors with F-actin and cytoskeleton readouts; promoter mapping\",\n      \"journal\": \"Experimental cell research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — EMSA and ChIP provide direct evidence of TF binding, complemented by siRNA functional readouts, single lab\",\n      \"pmids\": [\"38253280\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"In RPMI-7951 melanoma cells, KANK2 is present in both integrin αVβ5 focal adhesions (FAs) and integrin α5β1 fibrillar adhesions (FBs); at FAs it functionally interacts with talin1 to maintain FA integrity and with talin2 to regulate FA dynamics; at FBs, KANK2 knockdown mimics integrin α5 knockdown by increasing microtubule-dependent cell migration, indicating KANK2 links FBs to microtubules and stabilizes them.\",\n      \"method\": \"siRNA knockdown; mass spectrometry of isolated integrin adhesion complexes; proximity ligation assay; live-cell imaging; Transwell migration assay; paclitaxel sensitivity assay\",\n      \"journal\": \"Cell communication and signaling : CCS\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — proximity ligation assays, MS proteomics, and functional siRNA phenotyping with multiple orthogonal readouts, single lab\",\n      \"pmids\": [\"41776630\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"KANK2 is a scaffold protein that localizes to the lateral border of focal adhesions and to fibrillar adhesions, where its KN motif directly binds the talin rod domain (preferentially talin2 in αVβ5-dominant cells, talin1 or talin2 in mixed-adhesion contexts) to activate talin/integrins while uncoupling the talin–actomyosin linkage, thereby reducing integrin tension and modulating cell migration speed; its C-terminal ankyrin repeat domain recruits KIF21A and links adhesions to the cortical microtubule stabilization complex to control microtubule dynamics, and a disease-causing mutation (S684F) pathologically redirects this binding site to eIF4A1, competitively displacing KIF21A and causing podocyte dysfunction; additionally, KANK2 sequesters steroid receptor coactivators (SRC-2/3) in the cytoplasm to limit VDR-driven transcription, and physically interacts with HSP70 to suppress AIF-mediated apoptosis.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"KANK2 is a scaffold protein of integrin adhesion complexes that couples adhesions to the microtubule cytoskeleton and tunes the mechanical link between integrins and actomyosin [#0, #3]. It accumulates at the lateral border of focal adhesions and in central sliding adhesions, where its N-terminal KN motif directly binds the talin rod domain to activate talin and integrins while diminishing the talin\\u2013actomyosin linkage, thereby lowering force transmission across integrins and promoting central adhesion sliding [#0]. Its C-terminal ankyrin repeat domain directly engages a short helical KIF21A peptide at two distinct pockets, as resolved by crystallography, recruiting the cortical microtubule stabilization complex to adhesions and controlling microtubule dynamics and cell migration [#2, #3]. In integrin \\u03b1V\\u03b25-dependent cells KANK2 acts preferentially through talin2 to regulate actin\\u2013microtubule crosstalk and drug sensitivity, while in mixed-adhesion contexts it engages talin1 for focal adhesion integrity and talin2 for dynamics and additionally links \\u03b15\\u03b21 fibrillar adhesions to stabilized microtubules [#6, #9]. A nephrotic-syndrome\\u2013associated mutation (S684F) creates a gain-of-binding site for eIF4A1 that competitively displaces KIF21A and abolishes the ability of KANK2 to rescue focal adhesion structure in knockout podocytes, converting a gain of binding into functional loss [#4]. Independent of its adhesion role, KANK2 sequesters steroid receptor coactivators SRC-2 and SRC-3 in the cytoplasm to limit vitamin D receptor\\u2013driven transactivation [#1], and physically interacts with HSP70 to reduce AIF release and apoptosis in epithelial cells [#5].\",\n  \"teleology\": [\n    {\n      \"year\": 2014,\n      \"claim\": \"Established a first molecular function for KANK2 by showing it retains transcriptional coactivators in the cytoplasm, with a disease mutation releasing them to the nucleus.\",\n      \"evidence\": \"Immunofluorescence of SRC-2/SRC-3 and vitamin D transactivation assays in patient vs. control keratinocytes, plus exome sequencing of the causative p.Ala670Val mutation\",\n      \"pmids\": [\"24671081\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Direct physical SRC-2/3\\u2013KANK2 binding interface not mapped\", \"Connection to the adhesion/microtubule role of KANK2 unestablished\", \"Single patient lineage\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Defined the core adhesion mechanism: KANK2 binds the talin rod via its KN motif to activate integrins while uncoupling talin from actomyosin, reducing integrin tension.\",\n      \"evidence\": \"Co-IP/pulldown mapping the KN motif\\u2013talin rod interaction, FRET integrin tension sensors, live-cell imaging and KN-motif mutagenesis across cell types\",\n      \"pmids\": [\"27548916\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Talin isoform preference not resolved in this study\", \"Quantitative contribution to migration left for later work\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Resolved the structural basis for microtubule coupling, showing how the KANK2 ankyrin domain captures a KIF21A peptide at two pockets.\",\n      \"evidence\": \"Crystal structures of the KANK2 ankyrin domain\\u2013KIF21A peptide complex with site-directed mutagenesis and biochemical binding assays\",\n      \"pmids\": [\"29183992\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Cellular consequences of disrupting the interface not tested here\", \"Whether the two pockets bind cooperatively unaddressed\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Placed KANK2 functionally within \\u03b1V\\u03b25 integrin adhesion complexes as the link to microtubules controlling drug sensitivity and migration.\",\n      \"evidence\": \"Mass spectrometry of isolated integrin adhesion complexes and siRNA knockdown with paclitaxel/vincristine sensitivity and migration assays\",\n      \"pmids\": [\"32195252\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Talin isoform mediating the link not identified\", \"Mechanism connecting microtubule stabilization to drug sensitivity unresolved\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Explained how a nephrotic-syndrome mutation acts: S684F gains an eIF4A1-binding site that competitively displaces KIF21A, producing functional loss of adhesion rescue.\",\n      \"evidence\": \"Crystal structure of KANK2(S684F)\\u2013eIF4A1, competitive binding assays, and rescue experiments in KANK2-knockout mouse podocytes\",\n      \"pmids\": [\"34274317\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Physiological role, if any, of eIF4A1 in wild-type podocytes unclear\", \"In vivo kidney phenotype of the mutation not established in this study\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Identified an anti-apoptotic role through HSP70, distinct from adhesion signaling.\",\n      \"evidence\": \"Reciprocal Co-IP of HSP70\\u2013KANK2, siRNA knockdown, hsp70.1 deletion in CLP mice, TUNEL staining and AIF release assays\",\n      \"pmids\": [\"35327602\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"KANK2 domain mediating HSP70 binding not mapped\", \"Mechanistic link between KANK2 and AIF retention unresolved\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Demonstrated talin isoform specificity, showing KANK2 acts through talin2 in \\u03b1V\\u03b25-reliant melanoma cells where KANK1 is dispensable.\",\n      \"evidence\": \"Talin1/talin2/KANK1/KANK2 siRNA, live-cell MT dynamics imaging, paclitaxel sensitivity and Transwell migration assays with adhesion-complex Western blots\",\n      \"pmids\": [\"37460977\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Generality across non-\\u03b1V\\u03b25 cell types untested in this study\", \"Direct talin2 binding interface not re-mapped\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Identified upstream transcriptional control of KANK2 expression governing actin cytoskeleton integrity.\",\n      \"evidence\": \"EMSA and ChIP for E2F1, TFAP2C and NRF1 binding to the KANK2 promoter plus siRNA knockdown with F-actin readouts in renal tubular epithelial cells\",\n      \"pmids\": [\"38253280\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Signals regulating these transcription factors on KANK2 unknown\", \"Direct vs. indirect cytoskeletal effects of TF knockdown not separated\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Extended the model to fibrillar adhesions and dual talin engagement, showing KANK2 links both \\u03b1V\\u03b25 focal adhesions and \\u03b15\\u03b21 fibrillar adhesions to stabilized microtubules.\",\n      \"evidence\": \"siRNA knockdown, MS of isolated adhesion complexes, proximity ligation assays, live-cell imaging, migration and paclitaxel sensitivity assays in RPMI-7951 cells\",\n      \"pmids\": [\"41776630\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Structural basis for talin1 vs. talin2 selectivity not resolved\", \"How a single KN motif partitions between adhesion types unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How KANK2's distinct activities\\u2014talin/integrin scaffolding, coactivator sequestration, and HSP70/AIF-dependent apoptosis suppression\\u2014are integrated within a single cell remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"No unifying study connecting the adhesion and non-adhesion roles\", \"Regulation governing which interaction dominates in a given context unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 2, 3]},\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [0, 3]},\n      {\"term_id\": \"GO:0140313\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 3, 9]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1474244\", \"supporting_discovery_ids\": [0, 3, 9]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"complexes\": [\"cortical microtubule stabilization complex (CMSC)\", \"integrin \\u03b1V\\u03b25 adhesion complex\"],\n    \"partners\": [\"TLN1\", \"TLN2\", \"KIF21A\", \"EIF4A1\", \"HSPA1A\", \"NCOA2\", \"NCOA3\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}