{"gene":"SORCS1","run_date":"2026-06-10T07:46:38","timeline":{"discoveries":[{"year":2002,"finding":"Human SorCS1 exists as three isoforms (SorCS1a, b, c) with completely different cytoplasmic tails. SorCS1 is synthesized as a proreceptor and converted in late Golgi compartments by furin-mediated cleavage. The isoforms mediate different trafficking: SorCS1a shows ~10% surface expression with rapid endocytosis, SorCS1b shows high surface expression with essentially no endocytosis, and SorCS1c is intermediate.","method":"Biochemical characterization of transfected cells; antibody-mediated endocytosis assay; furin cleavage assay","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct functional assays in transfected cells with multiple isoforms tested, single lab","pmids":["12482870"],"is_preprint":false},{"year":2008,"finding":"SorCS1c is internalized through a canonical tyrosine-based motif, while human SorCS1a is internalized through a DXXLL motif. Human SorCS1a cytoplasmic domain interacts with the αC/σ2 subunits of the AP-2 adaptor protein complex. Internalization of human SorCS1a and SorCS1c is mediated by AP-2. The endocytic isoforms target internalized cargo to lysosomes but are not significantly engaged in Golgi-endosomal transport.","method":"Mutagenesis of sorting motifs; co-immunoprecipitation with AP-2 subunits; endocytosis assays in transfected cells; in situ hybridization","journal":"Traffic (Copenhagen, Denmark)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — motif mutagenesis plus co-IP with AP-2, single lab, two orthogonal methods","pmids":["18315530"],"is_preprint":false},{"year":2010,"finding":"SorCS1 forms complexes with APP, SorL1, and Vps35 (retromer) in non-transgenic mouse brain. Overexpression of SorCS1cβ-myc in cultured cells reduces Aβ generation. Sorcs1-hypomorphic female mice show increased endogenous murine Aβ40 and Aβ42 brain levels, and decreased total Vps35 (49%) and SorL1 (29%) protein levels.","method":"Co-immunoprecipitation from mouse brain; overexpression in cultured cells with Aβ ELISA; Sorcs1 hypomorphic mouse model with protein quantification","journal":"The Journal of neuroscience : the official journal of the Society for Neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP from native brain plus genetic mouse model with two orthogonal readouts, single lab","pmids":["20881129"],"is_preprint":false},{"year":2011,"finding":"Overexpression of SorCS1 reduces γ-secretase activity and Aβ levels, while suppression of SorCS1 increases γ-secretase processing of APP and Aβ levels in cultured cells.","method":"SorCS1 overexpression and siRNA knockdown in cultured cells; γ-secretase activity assay; Aβ ELISA","journal":"Annals of neurology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — bidirectional manipulation (OE and KD) with direct enzymatic and peptide readouts, single lab","pmids":["21280075"],"is_preprint":false},{"year":2013,"finding":"A specific sorting motif in the SorCS1c cytoplasmic tail controls APP sorting: mutation of this motif results in perturbed sorting of APP and/or its fragments to endosomal compartments, decreased retrograde TGN trafficking, and increased Aβ production. This effect acts on intracellular APP downstream of endocytosis, not on cell surface APP turnover.","method":"Cytoplasmic tail motif mutagenesis; subcellular fractionation; Aβ ELISA in H4 neuroglioma cells","journal":"The Journal of neuroscience : the official journal of the Society for Neuroscience","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — direct mutagenesis of functional motif with mechanistic readouts, single lab","pmids":["23595767"],"is_preprint":false},{"year":2014,"finding":"Whole-body Sorcs1 KO mice made obese (ob/ob) developed diabetes with severe deficiency of secretory granules (SGs) and insulin in β cells. Expression of the luminal domain of SORCS1 (Lum-Sorcs1) as a dominant-negative in β cell lines caused SG and insulin deficiency. Loss of Sorcs1 greatly impairs rapid replenishment of SGs following secretagogue challenge (shown by syncollin-dsRed5TIMER adenovirus). Overexpression of full-length SORCS1 led to a 2-fold increase in SG content, establishing SORCS1 as sufficient to promote SG biogenesis.","method":"Sorcs1 KO ob/ob mouse model; dominant-negative Lum-Sorcs1 overexpression in β cell line; syncollin-dsRed5TIMER adenoviral pulse-chase for granule replenishment; full-length SORCS1 overexpression with granule quantification","journal":"The Journal of clinical investigation","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic KO, dominant-negative, and overexpression approaches with multiple orthogonal functional readouts in the same study","pmids":["25157818"],"is_preprint":false},{"year":2014,"finding":"Human sorCS1 propeptide region contains two separate binding sites for sortilin; mature human (but not mouse) sorCS1 retains one sortilin-binding site after furin processing, allowing complex formation between mature sorCS1 and sortilin on cell membranes. This interaction hampers sortilin-mediated cellular uptake of alternative ligands and inhibits sortilin's facilitation of CNTF signaling and phospho-STAT3 induction.","method":"Binding assays; co-immunoprecipitation; cellular uptake assays; STAT3 phosphorylation assay; species-comparison of processing","journal":"The Biochemical journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct binding and functional inhibition assays with mechanistic dissection, single lab","pmids":["24128306"],"is_preprint":false},{"year":2015,"finding":"SorCS1 localizes to early and recycling endosomes and regulates neurexin and AMPA receptor (AMPAR) surface trafficking. Four independent proteomic analyses identify neurexin and AMPARs as major proteins sorted by SorCS1. SorCS1-deficient neurons have decreased surface levels of neurexins and AMPARs, and glutamatergic transmission is reduced due to impaired AMPAR surface expression.","method":"Four independent proteomic analyses; surface proteome analysis of SorCS1-KO neurons; subcellular fractionation/localization; electrophysiology of SorCS1-KO synapses","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 2 / Strong — four independent proteomic datasets plus KO surface proteomics plus electrophysiology, multiple orthogonal methods","pmids":["26291160"],"is_preprint":false},{"year":2015,"finding":"SorCS1b and SorCS1c are co-transported with APP by fast anterograde axonal transport, with ~30% of anterograde APP-positive vesicles containing SorCS1. SorCS1c (but not SorCS1b) reduces the anterograde transport rate of APP and increases the number of APP-positive stationary vesicles. SorCS1c and APP are internalized independently but share a common post-endocytic pathway.","method":"Live-cell imaging of Venus-tagged SorCS1 and APP in neurons; vesicle tracking; co-immunoprecipitation; co-localization studies","journal":"Journal of neurochemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — live imaging with functional Venus constructs plus Co-IP, single lab, isoform-specific dissection","pmids":["26119586"],"is_preprint":false},{"year":2018,"finding":"SORCS1 and SORCS3 act as intracellular trafficking receptors for tropomyosin-related kinase B (TrkB) to attenuate BDNF signaling in arcuate nucleus neurons. Loss of joint SORCS1/SORCS3 action results in excessive production of orexigenic neuropeptide agouti-related peptide (AgRP), enhanced food intake, and altered energy homeostasis.","method":"Individual and dual Sorcs1/Sorcs3 KO mouse models; TrkB co-trafficking assays; metabolic phenotyping; neuropeptide quantification","journal":"EMBO reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic mouse models with defined molecular pathway placement (TrkB trafficking), single lab","pmids":["29440124"],"is_preprint":false},{"year":2019,"finding":"SorCS1 maintains axonal surface polarization of neurexin1α (Nrxn1α) by facilitating transition of internalized Nrxn1α from early to recycling endosomes via interaction with Rab11 GTPase effector Rab11FIP5/Rip11. Without SorCS1, Nrxn1α accumulates in early endosomes and mispolarizes to the dendritic surface, impairing presynaptic differentiation and function.","method":"SorCS1 KO neurons with live imaging and endosomal tracking; Co-IP of SorCS1 with Rab11FIP5; surface polarization assays; presynaptic function measurements","journal":"PLoS biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — KO with defined molecular interaction (Rab11FIP5 Co-IP), live endosomal trafficking, and presynaptic functional readout, multiple orthogonal methods","pmids":["31658245"],"is_preprint":false},{"year":2019,"finding":"The Sorcs1 Thr52Ile mutation (T2DM-associated) causes differential processing of the Sorcs1 protein in INS1 β cells, producing an additional 90 kDa mutant form that is localized to the ER, retains its pro-domain, and reduces expression of the functional mature 130 kDa Sorcs1 protein. Expression of Thr52Ile is associated with increased basal insulin secretion, reduced glucose-stimulated insulin secretion, and decreased insulin content.","method":"INS1 β-cell line expressing wildtype or mutant Sorcs1; protein size analysis by western blot; subcellular fractionation/ER localization; insulin secretion assays","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct comparison of WT vs. mutant protein processing with multiple functional readouts, single lab","pmids":["31857633"],"is_preprint":false},{"year":2023,"finding":"The SorCS1 ectodomain competes with amyloid-β oligomers (AβOs) for binding to NRX1β through the histidine-rich domain of NRX1β. SorCS1b colocalizes with NRX1β on the axon surface, and axonal expression of SorCS1b rescues AβO-induced impairment of NRX-mediated presynaptic organization, presynaptic vesicle recycling, and structural defects in excitatory synapses.","method":"Binding competition assay (SorCS1 ectodomain vs. AβOs for NRX1β); live imaging of SorCS1b and NRX1β colocalization; functional rescue experiments in hippocampal neurons with synaptic readouts","journal":"Life science alliance","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct binding competition plus neuronal rescue experiments with functional synaptic readouts, single lab","pmids":["36697254"],"is_preprint":false},{"year":2024,"finding":"The SorCS1-3 intracellular domains contain a conserved triple serine motif; phosphorylation-mimicking mutations of these serines in SorCS1 display neurotrophic activity independently of the extracellular domain and BDNF, while serine-to-alanine substitutions render neurons less responsive to BDNF. Triple serine motif-based cell-penetrating peptides modulate downstream BDNF pathway kinases and activate the transcription factor CREB.","method":"Phosphomimetic and alanine mutagenesis; hippocampal neuron functional assays; cell-penetrating peptide experiments; CREB activation assay","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — mutagenesis with functional readouts, preprint not yet peer-reviewed, single lab","pmids":[],"is_preprint":true}],"current_model":"SorCS1 is a Vps10p-domain sorting receptor expressed in neurons and β cells that exists as multiple alternatively spliced isoforms with distinct cytoplasmic tails (differing in endocytic motifs and AP-2 interactions) dictating their trafficking itineraries; it localizes to early and recycling endosomes where it sorts key cargo—including neurexins, AMPA receptors, APP, and TrkB—by facilitating endosomal transition via Rab11FIP5/Rab11 to bias axonal surface polarization, attenuate BDNF/TrkB signaling, and reduce amyloidogenic APP processing through retromer-dependent TGN retrieval, while in pancreatic β cells it is required for secretory granule biogenesis and replenishment under metabolic stress."},"narrative":{"mechanistic_narrative":"SORCS1 is a Vps10p-domain sorting receptor that governs the endosomal trafficking of synaptic and amyloidogenic cargo in neurons and is required for secretory granule biogenesis in pancreatic β cells [PMID:26291160, PMID:25157818]. It is synthesized as a furin-processed proreceptor and expressed as alternatively spliced isoforms (SorCS1a/b/c) whose distinct cytoplasmic tails specify trafficking: endocytic isoforms internalize via tyrosine-based or DXXLL motifs that recruit the AP-2 adaptor complex, while non-endocytic isoforms persist at the surface [PMID:12482870, PMID:18315530]. Localized to early and recycling endosomes, SorCS1 sorts neurexins and AMPA receptors to maintain glutamatergic transmission, and it preserves axonal surface polarization of neurexin-1α by routing internalized cargo from early to recycling endosomes through interaction with the Rab11 effector Rab11FIP5 [PMID:26291160, PMID:31658245]. SorCS1 forms complexes with APP, SORL1, and the retromer subunit VPS35 and limits amyloidogenic processing: it controls intracellular APP sorting and retrograde TGN retrieval downstream of endocytosis, reducing γ-secretase activity and Aβ generation [PMID:20881129, PMID:21280075, PMID:23595767]. Through its ectodomain it also competes with amyloid-β oligomers for binding to neurexin-1β and rescues AβO-induced presynaptic defects [PMID:36697254]. Acting with SORCS3, it serves as an intracellular trafficking receptor for TrkB to attenuate BDNF signaling and regulate energy homeostasis [PMID:29440124]. In β cells SORCS1 is required for secretory granule and insulin content and for rapid granule replenishment under metabolic stress, and a T2DM-associated Thr52Ile variant misprocesses the receptor, retaining it in the ER and impairing glucose-stimulated insulin secretion [PMID:25157818, PMID:31857633].","teleology":[{"year":2002,"claim":"Established that SORCS1 is a furin-processed receptor whose alternatively spliced isoforms carry distinct cytoplasmic tails dictating divergent surface-versus-endocytic behavior, setting up isoform-specific trafficking as the central logic of the protein.","evidence":"Biochemical characterization, furin cleavage and antibody-mediated endocytosis assays in transfected cells","pmids":["12482870"],"confidence":"Medium","gaps":["Cargo sorted by each isoform not yet identified","Endosomal itinerary not defined","Single cell-line system"]},{"year":2008,"claim":"Resolved the molecular basis of isoform internalization by mapping a tyrosine-based motif in SorCS1c and a DXXLL motif in SorCS1a that recruit the AP-2 adaptor to drive endocytosis toward lysosomes.","evidence":"Sorting-motif mutagenesis and AP-2 subunit co-immunoprecipitation in transfected cells","pmids":["18315530"],"confidence":"Medium","gaps":["Physiological cargo not identified","Golgi-endosomal transport role excluded but alternative routes unclear"]},{"year":2010,"claim":"Placed SORCS1 in the retromer/SORL1 sorting axis controlling APP, linking the receptor to amyloid processing in vivo.","evidence":"Reciprocal Co-IP from native mouse brain plus Sorcs1-hypomorphic mouse with Aβ and protein quantification","pmids":["20881129"],"confidence":"Medium","gaps":["Direct vs. indirect APP interaction unresolved","Sex-specific phenotype mechanism unknown"]},{"year":2011,"claim":"Demonstrated bidirectional control of amyloidogenesis, showing SORCS1 levels inversely set γ-secretase processing of APP and Aβ output.","evidence":"Overexpression and siRNA knockdown with γ-secretase activity assay and Aβ ELISA in cultured cells","pmids":["21280075"],"confidence":"Medium","gaps":["Mechanism connecting SORCS1 to γ-secretase not defined"]},{"year":2013,"claim":"Identified a discrete SorCS1c cytoplasmic motif that routes intracellular APP to retrograde TGN trafficking, defining where in the pathway SORCS1 acts on amyloid production.","evidence":"Cytoplasmic-tail motif mutagenesis with subcellular fractionation and Aβ ELISA in H4 cells","pmids":["23595767"],"confidence":"Medium","gaps":["Adaptor recognizing this motif not identified","Surface APP turnover explicitly unaffected, leaving compartment-specific machinery open"]},{"year":2014,"claim":"Revealed a non-neuronal function: SORCS1 is necessary and sufficient for secretory granule biogenesis and rapid replenishment in β cells, connecting it to insulin storage and diabetes.","evidence":"Sorcs1 KO ob/ob mice, dominant-negative luminal domain, and overexpression with granule pulse-chase reporters","pmids":["25157818"],"confidence":"High","gaps":["Molecular cargo for granule biogenesis not identified","Endosomal vs. Golgi route in β cells unclear"]},{"year":2014,"claim":"Showed mature human SORCS1 retains a sortilin-binding site enabling a membrane complex that antagonizes sortilin-mediated uptake and CNTF/STAT3 signaling, establishing receptor-receptor regulation.","evidence":"Binding/Co-IP, cellular uptake and STAT3 phosphorylation assays with human-vs-mouse processing comparison","pmids":["24128306"],"confidence":"Medium","gaps":["Physiological relevance of the human-specific interaction in vivo untested"]},{"year":2015,"claim":"Defined SORCS1 as an early/recycling endosomal sorting receptor for neurexins and AMPA receptors required for glutamatergic transmission, broadening its role to synaptic surface trafficking.","evidence":"Four independent proteomic datasets, KO surface proteomics, localization, and electrophysiology","pmids":["26291160"],"confidence":"High","gaps":["Sorting motifs for these cargoes not mapped","Recycling machinery not yet identified"]},{"year":2015,"claim":"Showed isoform-specific co-transport of SORCS1 with APP in axons, with SorCS1c slowing APP anterograde transport and increasing stationary vesicles, linking trafficking dynamics to amyloid handling.","evidence":"Live-cell imaging of Venus-tagged constructs, vesicle tracking, and Co-IP in neurons","pmids":["26119586"],"confidence":"Medium","gaps":["Functional consequence of slowed transport on Aβ not quantified","Independent internalization but shared post-endocytic pathway not mechanistically detailed"]},{"year":2018,"claim":"Established SORCS1 (with SORCS3) as an intracellular trafficking receptor for TrkB that attenuates BDNF signaling and regulates feeding via AgRP, extending its role to central energy homeostasis.","evidence":"Single and dual Sorcs1/Sorcs3 KO mice with TrkB co-trafficking, metabolic phenotyping and neuropeptide quantification","pmids":["29440124"],"confidence":"Medium","gaps":["Redundancy structure between SORCS1 and SORCS3 not dissected","Direct TrkB binding interface unmapped"]},{"year":2019,"claim":"Identified the recycling-endosome machinery for SORCS1, showing it engages Rab11FIP5/Rab11 to move internalized neurexin-1α from early to recycling endosomes and maintain axonal polarization required for presynaptic function.","evidence":"KO neurons with live endosomal tracking, Rab11FIP5 Co-IP, and presynaptic functional assays","pmids":["31658245"],"confidence":"High","gaps":["Whether the same Rab11FIP5 route handles AMPAR/APP not established"]},{"year":2019,"claim":"Provided a molecular mechanism for a T2DM-associated variant, showing Thr52Ile misprocesses SORCS1 into an ER-retained pro-domain-bearing form that reduces mature receptor and impairs glucose-stimulated insulin secretion.","evidence":"INS1 β cells expressing WT vs. mutant with western blot, ER localization and insulin secretion assays","pmids":["31857633"],"confidence":"Medium","gaps":["In vivo confirmation in human islets absent","Link between ER retention and granule phenotype not directly demonstrated"]},{"year":2023,"claim":"Showed the SORCS1 ectodomain protects synapses by competing with amyloid-β oligomers for neurexin-1β binding, providing an extracellular protective mechanism distinct from intracellular sorting.","evidence":"Binding competition for NRX1β, colocalization imaging, and functional rescue in hippocampal neurons","pmids":["36697254"],"confidence":"Medium","gaps":["In vivo neuroprotection not tested","Whether competition occurs at physiological SORCS1 levels unclear"]},{"year":2024,"claim":"Indicated a signaling-competent intracellular triple-serine motif whose phosphorylation state confers BDNF-independent neurotrophic activity converging on CREB.","evidence":"Phosphomimetic/alanine mutagenesis and cell-penetrating peptide assays in hippocampal neurons (preprint)","pmids":[],"confidence":"Medium","gaps":["Preprint, not peer-reviewed","Kinase phosphorylating the motif not identified","Endogenous relevance vs. peptide artifact unresolved"]},{"year":null,"claim":"How a single sorting receptor integrates its distinct cargo (neurexins, AMPARs, APP, TrkB) through shared versus cargo-specific endosomal machinery, and how its β-cell granule role mechanistically relates to its neuronal sorting function, remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unifying biochemical model of cargo recognition","Structural basis of cargo binding undefined","Tissue-specific itinerary differences unexplained"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0038024","term_label":"cargo receptor activity","supporting_discovery_ids":[7,10,9]},{"term_id":"GO:0060089","term_label":"molecular transducer activity","supporting_discovery_ids":[6,9]}],"localization":[{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[7,10]},{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[0,4]},{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[11]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,6,12]}],"pathway":[{"term_id":"R-HSA-9609507","term_label":"Protein localization","supporting_discovery_ids":[7,10,4]},{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[1,8,10]},{"term_id":"R-HSA-112316","term_label":"Neuronal System","supporting_discovery_ids":[7,12]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[2,3,11]}],"complexes":["retromer (SORCS1–SORL1–VPS35)"],"partners":["APP","SORL1","VPS35","AP-2","NRXN1","RAB11FIP5","SORT1","TRKB"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q8WY21","full_name":"VPS10 domain-containing receptor SorCS1","aliases":[],"length_aa":1168,"mass_kda":129.6,"function":"","subcellular_location":"Membrane","url":"https://www.uniprot.org/uniprotkb/Q8WY21/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/SORCS1","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":[],"url":"https://opencell.sf.czbiohub.org/search/SORCS1","total_profiled":1310},"omim":[{"mim_id":"606285","title":"SORTILIN-RELATED VPS10 DOMAIN-CONTAINING RECEPTOR 3; SORCS3","url":"https://www.omim.org/entry/606285"},{"mim_id":"606284","title":"SORTILIN-RELATED VPS10 DOMAIN-CONTAINING RECEPTOR 2; SORCS2","url":"https://www.omim.org/entry/606284"},{"mim_id":"606283","title":"SORTILIN-RELATED VPS10 DOMAIN-CONTAINING RECEPTOR 1; SORCS1","url":"https://www.omim.org/entry/606283"},{"mim_id":"605526","title":"ALZHEIMER DISEASE 6","url":"https://www.omim.org/entry/605526"},{"mim_id":"602458","title":"SORTILIN; SORT1","url":"https://www.omim.org/entry/602458"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Plasma membrane","reliability":"Approved"},{"location":"Cytosol","reliability":"Approved"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"brain","ntpm":10.1},{"tissue":"thyroid gland","ntpm":10.1}],"url":"https://www.proteinatlas.org/search/SORCS1"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"Q8WY21","domains":[{"cath_id":"2.130.10.120","chopping":"274-402","consensus_level":"medium","plddt":89.9297,"start":274,"end":402},{"cath_id":"2.10.70","chopping":"676-721","consensus_level":"medium","plddt":85.8757,"start":676,"end":721},{"cath_id":"3.30.60.270","chopping":"726-793","consensus_level":"high","plddt":87.276,"start":726,"end":793},{"cath_id":"2.60.40.10","chopping":"799-878","consensus_level":"high","plddt":85.8781,"start":799,"end":878},{"cath_id":"2.60.40.10","chopping":"893-974","consensus_level":"high","plddt":87.8733,"start":893,"end":974},{"cath_id":"-","chopping":"978-1041_1053-1087","consensus_level":"medium","plddt":86.44,"start":978,"end":1087},{"cath_id":"2.40.128","chopping":"172-271","consensus_level":"medium","plddt":89.5481,"start":172,"end":271},{"cath_id":"2.40.128","chopping":"586-669","consensus_level":"medium","plddt":86.1582,"start":586,"end":669}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8WY21","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8WY21-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8WY21-F1-predicted_aligned_error_v6.png","plddt_mean":76.69},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=SORCS1","jax_strain_url":"https://www.jax.org/strain/search?query=SORCS1"},"sequence":{"accession":"Q8WY21","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8WY21.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8WY21/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8WY21"}},"corpus_meta":[{"pmid":"16682971","id":"PMC_16682971","title":"Positional cloning of Sorcs1, a type 2 diabetes quantitative trait locus.","date":"2006","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/16682971","citation_count":139,"is_preprint":false},{"pmid":"20881129","id":"PMC_20881129","title":"Diabetes-associated SorCS1 regulates Alzheimer's amyloid-beta metabolism: evidence for involvement of SorL1 and the retromer complex.","date":"2010","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/20881129","citation_count":133,"is_preprint":false},{"pmid":"21280075","id":"PMC_21280075","title":"SORCS1 alters amyloid precursor protein processing and variants may increase Alzheimer's disease risk.","date":"2011","source":"Annals of neurology","url":"https://pubmed.ncbi.nlm.nih.gov/21280075","citation_count":105,"is_preprint":false},{"pmid":"17426289","id":"PMC_17426289","title":"SORCS1: a novel human type 2 diabetes susceptibility gene suggested by the mouse.","date":"2007","source":"Diabetes","url":"https://pubmed.ncbi.nlm.nih.gov/17426289","citation_count":78,"is_preprint":false},{"pmid":"26291160","id":"PMC_26291160","title":"The Sorting Receptor SorCS1 Regulates Trafficking of Neurexin and AMPA Receptors.","date":"2015","source":"Neuron","url":"https://pubmed.ncbi.nlm.nih.gov/26291160","citation_count":73,"is_preprint":false},{"pmid":"29440124","id":"PMC_29440124","title":"SORCS1 and SORCS3 control energy balance and orexigenic peptide production.","date":"2018","source":"EMBO reports","url":"https://pubmed.ncbi.nlm.nih.gov/29440124","citation_count":45,"is_preprint":false},{"pmid":"25157818","id":"PMC_25157818","title":"SORCS1 is necessary for normal insulin secretory granule biogenesis in metabolically stressed β cells.","date":"2014","source":"The Journal of clinical investigation","url":"https://pubmed.ncbi.nlm.nih.gov/25157818","citation_count":45,"is_preprint":false},{"pmid":"31658245","id":"PMC_31658245","title":"SorCS1-mediated sorting in dendrites maintains neurexin axonal surface polarization required for synaptic function.","date":"2019","source":"PLoS biology","url":"https://pubmed.ncbi.nlm.nih.gov/31658245","citation_count":42,"is_preprint":false},{"pmid":"12482870","id":"PMC_12482870","title":"Characterization of sorCS1, an alternatively spliced receptor with completely different cytoplasmic domains that mediate different trafficking in cells.","date":"2002","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/12482870","citation_count":41,"is_preprint":false},{"pmid":"23595767","id":"PMC_23595767","title":"Protein sorting motifs in the cytoplasmic tail of SorCS1 control generation of Alzheimer's amyloid-β peptide.","date":"2013","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/23595767","citation_count":38,"is_preprint":false},{"pmid":"18315530","id":"PMC_18315530","title":"Different motifs regulate trafficking of SorCS1 isoforms.","date":"2008","source":"Traffic (Copenhagen, Denmark)","url":"https://pubmed.ncbi.nlm.nih.gov/18315530","citation_count":36,"is_preprint":false},{"pmid":"11684345","id":"PMC_11684345","title":"SorCS1, a member of the novel sorting receptor family, is localized in somata and dendrites of neurons throughout the murine brain.","date":"2001","source":"Neuroscience letters","url":"https://pubmed.ncbi.nlm.nih.gov/11684345","citation_count":30,"is_preprint":false},{"pmid":"22353753","id":"PMC_22353753","title":"SORCS1 and APOE polymorphisms interact to confer risk for late-onset Alzheimer's disease in a Northern Han Chinese population.","date":"2012","source":"Brain research","url":"https://pubmed.ncbi.nlm.nih.gov/22353753","citation_count":26,"is_preprint":false},{"pmid":"26916443","id":"PMC_26916443","title":"Unexpected partial correction of metabolic and behavioral phenotypes of Alzheimer's APP/PSEN1 mice by gene targeting of diabetes/Alzheimer's-related Sorcs1.","date":"2016","source":"Acta neuropathologica communications","url":"https://pubmed.ncbi.nlm.nih.gov/26916443","citation_count":21,"is_preprint":false},{"pmid":"26119586","id":"PMC_26119586","title":"SorCS1 variants and amyloid precursor protein (APP) are co-transported in neurons but only SorCS1c modulates anterograde APP transport.","date":"2015","source":"Journal of neurochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/26119586","citation_count":19,"is_preprint":false},{"pmid":"23700427","id":"PMC_23700427","title":"The genetic variation of SORCS1 is associated with late-onset Alzheimer's disease in Chinese Han population.","date":"2013","source":"PloS 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expression.","date":"2021","source":"Aging","url":"https://pubmed.ncbi.nlm.nih.gov/34326275","citation_count":8,"is_preprint":false},{"pmid":"31857633","id":"PMC_31857633","title":"Type 2 diabetes-associated single nucleotide polymorphism in Sorcs1 gene results in alternative processing of the Sorcs1 protein in INS1 β-cells.","date":"2019","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/31857633","citation_count":7,"is_preprint":false},{"pmid":"28535629","id":"PMC_28535629","title":"[Association between SORCS1 rs1416406 and therapeutic effect of exenatide].","date":"2017","source":"Zhonghua yi xue za zhi","url":"https://pubmed.ncbi.nlm.nih.gov/28535629","citation_count":7,"is_preprint":false},{"pmid":"31605284","id":"PMC_31605284","title":"Up-Regulation of SorCS1, an Important Sorting Receptor, in the Retina of a Form-Deprivation Rat Model.","date":"2019","source":"Cellular and molecular neurobiology","url":"https://pubmed.ncbi.nlm.nih.gov/31605284","citation_count":5,"is_preprint":false},{"pmid":"41701742","id":"PMC_41701742","title":"Identification of SORCS1 as a candidate gene associated with canine behavioral traits: Insights from guide dog training outcomes.","date":"2026","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/41701742","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.11.18.25340532","title":"Common and rare variant genetic contributions in African Americans with autism","date":"2025-11-19","source":"bioRxiv","url":"https://doi.org/10.1101/2025.11.18.25340532","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2024.10.03.616089","title":"A triple serine motif in the intracellular domains of sortilin-related receptors SorCS1-3 regulates neurotrophic activity","date":"2024-10-03","source":"bioRxiv","url":"https://doi.org/10.1101/2024.10.03.616089","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2024.09.04.24313052","title":"Pharmacogenetic Study of Antipsychotic-Induced Lipid and BMI Changes in Chinese Schizophrenia Patients: A Genome-Wide Association Study","date":"2024-09-04","source":"bioRxiv","url":"https://doi.org/10.1101/2024.09.04.24313052","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":16837,"output_tokens":3907,"usd":0.054558,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":11700,"output_tokens":4588,"usd":0.0866,"stage2_stop_reason":"end_turn"},"total_usd":0.141158,"stage1_batch_id":"msgbatch_013LWZZT6MWaqB9qyTSeQBmU","stage2_batch_id":"msgbatch_0194ZzQaTGNpruoNJBbEMbt3","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2002,\n      \"finding\": \"Human SorCS1 exists as three isoforms (SorCS1a, b, c) with completely different cytoplasmic tails. SorCS1 is synthesized as a proreceptor and converted in late Golgi compartments by furin-mediated cleavage. The isoforms mediate different trafficking: SorCS1a shows ~10% surface expression with rapid endocytosis, SorCS1b shows high surface expression with essentially no endocytosis, and SorCS1c is intermediate.\",\n      \"method\": \"Biochemical characterization of transfected cells; antibody-mediated endocytosis assay; furin cleavage assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct functional assays in transfected cells with multiple isoforms tested, single lab\",\n      \"pmids\": [\"12482870\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"SorCS1c is internalized through a canonical tyrosine-based motif, while human SorCS1a is internalized through a DXXLL motif. Human SorCS1a cytoplasmic domain interacts with the αC/σ2 subunits of the AP-2 adaptor protein complex. Internalization of human SorCS1a and SorCS1c is mediated by AP-2. The endocytic isoforms target internalized cargo to lysosomes but are not significantly engaged in Golgi-endosomal transport.\",\n      \"method\": \"Mutagenesis of sorting motifs; co-immunoprecipitation with AP-2 subunits; endocytosis assays in transfected cells; in situ hybridization\",\n      \"journal\": \"Traffic (Copenhagen, Denmark)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — motif mutagenesis plus co-IP with AP-2, single lab, two orthogonal methods\",\n      \"pmids\": [\"18315530\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"SorCS1 forms complexes with APP, SorL1, and Vps35 (retromer) in non-transgenic mouse brain. Overexpression of SorCS1cβ-myc in cultured cells reduces Aβ generation. Sorcs1-hypomorphic female mice show increased endogenous murine Aβ40 and Aβ42 brain levels, and decreased total Vps35 (49%) and SorL1 (29%) protein levels.\",\n      \"method\": \"Co-immunoprecipitation from mouse brain; overexpression in cultured cells with Aβ ELISA; Sorcs1 hypomorphic mouse model with protein quantification\",\n      \"journal\": \"The Journal of neuroscience : the official journal of the Society for Neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP from native brain plus genetic mouse model with two orthogonal readouts, single lab\",\n      \"pmids\": [\"20881129\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Overexpression of SorCS1 reduces γ-secretase activity and Aβ levels, while suppression of SorCS1 increases γ-secretase processing of APP and Aβ levels in cultured cells.\",\n      \"method\": \"SorCS1 overexpression and siRNA knockdown in cultured cells; γ-secretase activity assay; Aβ ELISA\",\n      \"journal\": \"Annals of neurology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — bidirectional manipulation (OE and KD) with direct enzymatic and peptide readouts, single lab\",\n      \"pmids\": [\"21280075\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"A specific sorting motif in the SorCS1c cytoplasmic tail controls APP sorting: mutation of this motif results in perturbed sorting of APP and/or its fragments to endosomal compartments, decreased retrograde TGN trafficking, and increased Aβ production. This effect acts on intracellular APP downstream of endocytosis, not on cell surface APP turnover.\",\n      \"method\": \"Cytoplasmic tail motif mutagenesis; subcellular fractionation; Aβ ELISA in H4 neuroglioma cells\",\n      \"journal\": \"The Journal of neuroscience : the official journal of the Society for Neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct mutagenesis of functional motif with mechanistic readouts, single lab\",\n      \"pmids\": [\"23595767\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Whole-body Sorcs1 KO mice made obese (ob/ob) developed diabetes with severe deficiency of secretory granules (SGs) and insulin in β cells. Expression of the luminal domain of SORCS1 (Lum-Sorcs1) as a dominant-negative in β cell lines caused SG and insulin deficiency. Loss of Sorcs1 greatly impairs rapid replenishment of SGs following secretagogue challenge (shown by syncollin-dsRed5TIMER adenovirus). Overexpression of full-length SORCS1 led to a 2-fold increase in SG content, establishing SORCS1 as sufficient to promote SG biogenesis.\",\n      \"method\": \"Sorcs1 KO ob/ob mouse model; dominant-negative Lum-Sorcs1 overexpression in β cell line; syncollin-dsRed5TIMER adenoviral pulse-chase for granule replenishment; full-length SORCS1 overexpression with granule quantification\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic KO, dominant-negative, and overexpression approaches with multiple orthogonal functional readouts in the same study\",\n      \"pmids\": [\"25157818\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Human sorCS1 propeptide region contains two separate binding sites for sortilin; mature human (but not mouse) sorCS1 retains one sortilin-binding site after furin processing, allowing complex formation between mature sorCS1 and sortilin on cell membranes. This interaction hampers sortilin-mediated cellular uptake of alternative ligands and inhibits sortilin's facilitation of CNTF signaling and phospho-STAT3 induction.\",\n      \"method\": \"Binding assays; co-immunoprecipitation; cellular uptake assays; STAT3 phosphorylation assay; species-comparison of processing\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct binding and functional inhibition assays with mechanistic dissection, single lab\",\n      \"pmids\": [\"24128306\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"SorCS1 localizes to early and recycling endosomes and regulates neurexin and AMPA receptor (AMPAR) surface trafficking. Four independent proteomic analyses identify neurexin and AMPARs as major proteins sorted by SorCS1. SorCS1-deficient neurons have decreased surface levels of neurexins and AMPARs, and glutamatergic transmission is reduced due to impaired AMPAR surface expression.\",\n      \"method\": \"Four independent proteomic analyses; surface proteome analysis of SorCS1-KO neurons; subcellular fractionation/localization; electrophysiology of SorCS1-KO synapses\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — four independent proteomic datasets plus KO surface proteomics plus electrophysiology, multiple orthogonal methods\",\n      \"pmids\": [\"26291160\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"SorCS1b and SorCS1c are co-transported with APP by fast anterograde axonal transport, with ~30% of anterograde APP-positive vesicles containing SorCS1. SorCS1c (but not SorCS1b) reduces the anterograde transport rate of APP and increases the number of APP-positive stationary vesicles. SorCS1c and APP are internalized independently but share a common post-endocytic pathway.\",\n      \"method\": \"Live-cell imaging of Venus-tagged SorCS1 and APP in neurons; vesicle tracking; co-immunoprecipitation; co-localization studies\",\n      \"journal\": \"Journal of neurochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — live imaging with functional Venus constructs plus Co-IP, single lab, isoform-specific dissection\",\n      \"pmids\": [\"26119586\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"SORCS1 and SORCS3 act as intracellular trafficking receptors for tropomyosin-related kinase B (TrkB) to attenuate BDNF signaling in arcuate nucleus neurons. Loss of joint SORCS1/SORCS3 action results in excessive production of orexigenic neuropeptide agouti-related peptide (AgRP), enhanced food intake, and altered energy homeostasis.\",\n      \"method\": \"Individual and dual Sorcs1/Sorcs3 KO mouse models; TrkB co-trafficking assays; metabolic phenotyping; neuropeptide quantification\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic mouse models with defined molecular pathway placement (TrkB trafficking), single lab\",\n      \"pmids\": [\"29440124\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"SorCS1 maintains axonal surface polarization of neurexin1α (Nrxn1α) by facilitating transition of internalized Nrxn1α from early to recycling endosomes via interaction with Rab11 GTPase effector Rab11FIP5/Rip11. Without SorCS1, Nrxn1α accumulates in early endosomes and mispolarizes to the dendritic surface, impairing presynaptic differentiation and function.\",\n      \"method\": \"SorCS1 KO neurons with live imaging and endosomal tracking; Co-IP of SorCS1 with Rab11FIP5; surface polarization assays; presynaptic function measurements\",\n      \"journal\": \"PLoS biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — KO with defined molecular interaction (Rab11FIP5 Co-IP), live endosomal trafficking, and presynaptic functional readout, multiple orthogonal methods\",\n      \"pmids\": [\"31658245\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"The Sorcs1 Thr52Ile mutation (T2DM-associated) causes differential processing of the Sorcs1 protein in INS1 β cells, producing an additional 90 kDa mutant form that is localized to the ER, retains its pro-domain, and reduces expression of the functional mature 130 kDa Sorcs1 protein. Expression of Thr52Ile is associated with increased basal insulin secretion, reduced glucose-stimulated insulin secretion, and decreased insulin content.\",\n      \"method\": \"INS1 β-cell line expressing wildtype or mutant Sorcs1; protein size analysis by western blot; subcellular fractionation/ER localization; insulin secretion assays\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct comparison of WT vs. mutant protein processing with multiple functional readouts, single lab\",\n      \"pmids\": [\"31857633\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"The SorCS1 ectodomain competes with amyloid-β oligomers (AβOs) for binding to NRX1β through the histidine-rich domain of NRX1β. SorCS1b colocalizes with NRX1β on the axon surface, and axonal expression of SorCS1b rescues AβO-induced impairment of NRX-mediated presynaptic organization, presynaptic vesicle recycling, and structural defects in excitatory synapses.\",\n      \"method\": \"Binding competition assay (SorCS1 ectodomain vs. AβOs for NRX1β); live imaging of SorCS1b and NRX1β colocalization; functional rescue experiments in hippocampal neurons with synaptic readouts\",\n      \"journal\": \"Life science alliance\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct binding competition plus neuronal rescue experiments with functional synaptic readouts, single lab\",\n      \"pmids\": [\"36697254\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"The SorCS1-3 intracellular domains contain a conserved triple serine motif; phosphorylation-mimicking mutations of these serines in SorCS1 display neurotrophic activity independently of the extracellular domain and BDNF, while serine-to-alanine substitutions render neurons less responsive to BDNF. Triple serine motif-based cell-penetrating peptides modulate downstream BDNF pathway kinases and activate the transcription factor CREB.\",\n      \"method\": \"Phosphomimetic and alanine mutagenesis; hippocampal neuron functional assays; cell-penetrating peptide experiments; CREB activation assay\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — mutagenesis with functional readouts, preprint not yet peer-reviewed, single lab\",\n      \"pmids\": [],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"SorCS1 is a Vps10p-domain sorting receptor expressed in neurons and β cells that exists as multiple alternatively spliced isoforms with distinct cytoplasmic tails (differing in endocytic motifs and AP-2 interactions) dictating their trafficking itineraries; it localizes to early and recycling endosomes where it sorts key cargo—including neurexins, AMPA receptors, APP, and TrkB—by facilitating endosomal transition via Rab11FIP5/Rab11 to bias axonal surface polarization, attenuate BDNF/TrkB signaling, and reduce amyloidogenic APP processing through retromer-dependent TGN retrieval, while in pancreatic β cells it is required for secretory granule biogenesis and replenishment under metabolic stress.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"SORCS1 is a Vps10p-domain sorting receptor that governs the endosomal trafficking of synaptic and amyloidogenic cargo in neurons and is required for secretory granule biogenesis in pancreatic \\u03b2 cells [#7, #5]. It is synthesized as a furin-processed proreceptor and expressed as alternatively spliced isoforms (SorCS1a/b/c) whose distinct cytoplasmic tails specify trafficking: endocytic isoforms internalize via tyrosine-based or DXXLL motifs that recruit the AP-2 adaptor complex, while non-endocytic isoforms persist at the surface [#0, #1]. Localized to early and recycling endosomes, SorCS1 sorts neurexins and AMPA receptors to maintain glutamatergic transmission, and it preserves axonal surface polarization of neurexin-1\\u03b1 by routing internalized cargo from early to recycling endosomes through interaction with the Rab11 effector Rab11FIP5 [#7, #10]. SorCS1 forms complexes with APP, SORL1, and the retromer subunit VPS35 and limits amyloidogenic processing: it controls intracellular APP sorting and retrograde TGN retrieval downstream of endocytosis, reducing \\u03b3-secretase activity and A\\u03b2 generation [#2, #3, #4]. Through its ectodomain it also competes with amyloid-\\u03b2 oligomers for binding to neurexin-1\\u03b2 and rescues A\\u03b2O-induced presynaptic defects [#12]. Acting with SORCS3, it serves as an intracellular trafficking receptor for TrkB to attenuate BDNF signaling and regulate energy homeostasis [#9]. In \\u03b2 cells SORCS1 is required for secretory granule and insulin content and for rapid granule replenishment under metabolic stress, and a T2DM-associated Thr52Ile variant misprocesses the receptor, retaining it in the ER and impairing glucose-stimulated insulin secretion [#5, #11].\",\n  \"teleology\": [\n    {\n      \"year\": 2002,\n      \"claim\": \"Established that SORCS1 is a furin-processed receptor whose alternatively spliced isoforms carry distinct cytoplasmic tails dictating divergent surface-versus-endocytic behavior, setting up isoform-specific trafficking as the central logic of the protein.\",\n      \"evidence\": \"Biochemical characterization, furin cleavage and antibody-mediated endocytosis assays in transfected cells\",\n      \"pmids\": [\"12482870\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Cargo sorted by each isoform not yet identified\", \"Endosomal itinerary not defined\", \"Single cell-line system\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Resolved the molecular basis of isoform internalization by mapping a tyrosine-based motif in SorCS1c and a DXXLL motif in SorCS1a that recruit the AP-2 adaptor to drive endocytosis toward lysosomes.\",\n      \"evidence\": \"Sorting-motif mutagenesis and AP-2 subunit co-immunoprecipitation in transfected cells\",\n      \"pmids\": [\"18315530\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Physiological cargo not identified\", \"Golgi-endosomal transport role excluded but alternative routes unclear\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Placed SORCS1 in the retromer/SORL1 sorting axis controlling APP, linking the receptor to amyloid processing in vivo.\",\n      \"evidence\": \"Reciprocal Co-IP from native mouse brain plus Sorcs1-hypomorphic mouse with A\\u03b2 and protein quantification\",\n      \"pmids\": [\"20881129\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct vs. indirect APP interaction unresolved\", \"Sex-specific phenotype mechanism unknown\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Demonstrated bidirectional control of amyloidogenesis, showing SORCS1 levels inversely set \\u03b3-secretase processing of APP and A\\u03b2 output.\",\n      \"evidence\": \"Overexpression and siRNA knockdown with \\u03b3-secretase activity assay and A\\u03b2 ELISA in cultured cells\",\n      \"pmids\": [\"21280075\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism connecting SORCS1 to \\u03b3-secretase not defined\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Identified a discrete SorCS1c cytoplasmic motif that routes intracellular APP to retrograde TGN trafficking, defining where in the pathway SORCS1 acts on amyloid production.\",\n      \"evidence\": \"Cytoplasmic-tail motif mutagenesis with subcellular fractionation and A\\u03b2 ELISA in H4 cells\",\n      \"pmids\": [\"23595767\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Adaptor recognizing this motif not identified\", \"Surface APP turnover explicitly unaffected, leaving compartment-specific machinery open\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Revealed a non-neuronal function: SORCS1 is necessary and sufficient for secretory granule biogenesis and rapid replenishment in \\u03b2 cells, connecting it to insulin storage and diabetes.\",\n      \"evidence\": \"Sorcs1 KO ob/ob mice, dominant-negative luminal domain, and overexpression with granule pulse-chase reporters\",\n      \"pmids\": [\"25157818\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular cargo for granule biogenesis not identified\", \"Endosomal vs. Golgi route in \\u03b2 cells unclear\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Showed mature human SORCS1 retains a sortilin-binding site enabling a membrane complex that antagonizes sortilin-mediated uptake and CNTF/STAT3 signaling, establishing receptor-receptor regulation.\",\n      \"evidence\": \"Binding/Co-IP, cellular uptake and STAT3 phosphorylation assays with human-vs-mouse processing comparison\",\n      \"pmids\": [\"24128306\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Physiological relevance of the human-specific interaction in vivo untested\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Defined SORCS1 as an early/recycling endosomal sorting receptor for neurexins and AMPA receptors required for glutamatergic transmission, broadening its role to synaptic surface trafficking.\",\n      \"evidence\": \"Four independent proteomic datasets, KO surface proteomics, localization, and electrophysiology\",\n      \"pmids\": [\"26291160\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Sorting motifs for these cargoes not mapped\", \"Recycling machinery not yet identified\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Showed isoform-specific co-transport of SORCS1 with APP in axons, with SorCS1c slowing APP anterograde transport and increasing stationary vesicles, linking trafficking dynamics to amyloid handling.\",\n      \"evidence\": \"Live-cell imaging of Venus-tagged constructs, vesicle tracking, and Co-IP in neurons\",\n      \"pmids\": [\"26119586\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequence of slowed transport on A\\u03b2 not quantified\", \"Independent internalization but shared post-endocytic pathway not mechanistically detailed\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Established SORCS1 (with SORCS3) as an intracellular trafficking receptor for TrkB that attenuates BDNF signaling and regulates feeding via AgRP, extending its role to central energy homeostasis.\",\n      \"evidence\": \"Single and dual Sorcs1/Sorcs3 KO mice with TrkB co-trafficking, metabolic phenotyping and neuropeptide quantification\",\n      \"pmids\": [\"29440124\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Redundancy structure between SORCS1 and SORCS3 not dissected\", \"Direct TrkB binding interface unmapped\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Identified the recycling-endosome machinery for SORCS1, showing it engages Rab11FIP5/Rab11 to move internalized neurexin-1\\u03b1 from early to recycling endosomes and maintain axonal polarization required for presynaptic function.\",\n      \"evidence\": \"KO neurons with live endosomal tracking, Rab11FIP5 Co-IP, and presynaptic functional assays\",\n      \"pmids\": [\"31658245\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether the same Rab11FIP5 route handles AMPAR/APP not established\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Provided a molecular mechanism for a T2DM-associated variant, showing Thr52Ile misprocesses SORCS1 into an ER-retained pro-domain-bearing form that reduces mature receptor and impairs glucose-stimulated insulin secretion.\",\n      \"evidence\": \"INS1 \\u03b2 cells expressing WT vs. mutant with western blot, ER localization and insulin secretion assays\",\n      \"pmids\": [\"31857633\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"In vivo confirmation in human islets absent\", \"Link between ER retention and granule phenotype not directly demonstrated\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Showed the SORCS1 ectodomain protects synapses by competing with amyloid-\\u03b2 oligomers for neurexin-1\\u03b2 binding, providing an extracellular protective mechanism distinct from intracellular sorting.\",\n      \"evidence\": \"Binding competition for NRX1\\u03b2, colocalization imaging, and functional rescue in hippocampal neurons\",\n      \"pmids\": [\"36697254\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"In vivo neuroprotection not tested\", \"Whether competition occurs at physiological SORCS1 levels unclear\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Indicated a signaling-competent intracellular triple-serine motif whose phosphorylation state confers BDNF-independent neurotrophic activity converging on CREB.\",\n      \"evidence\": \"Phosphomimetic/alanine mutagenesis and cell-penetrating peptide assays in hippocampal neurons (preprint)\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint, not peer-reviewed\", \"Kinase phosphorylating the motif not identified\", \"Endogenous relevance vs. peptide artifact unresolved\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How a single sorting receptor integrates its distinct cargo (neurexins, AMPARs, APP, TrkB) through shared versus cargo-specific endosomal machinery, and how its \\u03b2-cell granule role mechanistically relates to its neuronal sorting function, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unifying biochemical model of cargo recognition\", \"Structural basis of cargo binding undefined\", \"Tissue-specific itinerary differences unexplained\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0038024\", \"supporting_discovery_ids\": [7, 10, 9]},\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [6, 9]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [7, 10]},\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [0, 4]},\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [11]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 6, 12]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [7, 10, 4]},\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [1, 8, 10]},\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [7, 12]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [2, 3, 11]}\n    ],\n    \"complexes\": [\"retromer (SORCS1\\u2013SORL1\\u2013VPS35)\"],\n    \"partners\": [\"APP\", \"SORL1\", \"VPS35\", \"AP-2\", \"NRXN1\", \"Rab11FIP5\", \"SORT1\", \"TrkB\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"faith_supported":7,"faith_total":7,"faith_pct":100.0}}