{"gene":"SNCG","run_date":"2026-06-10T07:46:37","timeline":{"discoveries":[{"year":1997,"finding":"BCSG1 (SNCG) was identified as a breast cancer-specific gene whose predicted amino acid sequence has significant homology to the non-amyloid beta protein fragment of the Alzheimer's disease amyloid protein. In situ hybridization showed BCSG1 is undetectable in normal or benign breast lesions but expressed at high levels in advanced infiltrating breast cancer, suggesting a role in malignant progression.","method":"Direct differential cDNA sequencing; in situ hybridization","journal":"Cancer research","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — original identification by cDNA sequencing and in situ hybridization in a single study; provides structural homology and expression context but limited mechanistic follow-up","pmids":["9044857"],"is_preprint":false},{"year":1998,"finding":"Persyn (SNCG) is a cytosolic protein expressed predominantly in cell bodies and axons of primary sensory neurons, sympathetic neurons, and motoneurons — in contrast to other synucleins, which are presynaptic proteins of CNS neurons. Expression begins from the earliest stages of axonal outgrowth and is maintained throughout life. Persyn also becomes detectable in evolutionary recent brain regions by adulthood.","method":"Northern blotting, in situ hybridization, Western blotting, immunohistochemistry","journal":"The Journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — multiple orthogonal methods (Northern, ISH, Western, IHC) establishing distinct subcellular localization in a single study; no functional perturbation experiment","pmids":["9801372"],"is_preprint":false},{"year":1998,"finding":"The human persyn (SNCG) gene was localized to chromosome 10q23.2-q23.3. Antibody-based detection showed increased persyn protein levels in ageing cerebral cortex and in breast tumors. No tumor-specific coding mutations were found, but two linked coding-region polymorphisms were identified, suggesting that breast tumor development correlates with overexpression of the wild-type persyn protein rather than mutation.","method":"Antibody immunodetection (Western blot/IHC), genomic cloning and sequencing, chromosomal localization, mutation screening by sequencing","journal":"Human molecular genetics","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — chromosomal localization and protein-level detection with specific antibody; mutation screen provides mechanistic exclusion of coding mutation as driver","pmids":["9700196"],"is_preprint":false},{"year":2000,"finding":"SNCG mRNA expression in breast cancer cells is transcriptionally suppressed by the growth-inhibitory cytokine oncostatin M (OM), with suppression detectable within 30 min and mRNA below detectable levels by 24 h. Pulse-chase transcription rate measurements confirmed the effect occurs mainly at the transcriptional level. Stable overexpression of SNCG cDNA in MCF-7 cells (which lack endogenous SNCG) significantly stimulated anchorage-dependent and anchorage-independent cell growth, demonstrating a pro-proliferative role for SNCG.","method":"Transcriptional rate measurement; Western blot; stable transfection with SNCG cDNA; anchorage-dependent and soft-agar growth assays","journal":"Breast cancer research and treatment","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — multiple complementary methods (transcription rate, protein expression, functional gain-of-function growth assay) in a single study; establishes transcriptional regulation and pro-proliferative function","pmids":["11016747"],"is_preprint":false},{"year":2006,"finding":"Abnormal SNCG expression in ovarian cancer is associated with CpG island hypomethylation in exon 1 of the SNCG gene; 75.7% of SNCG mRNA-positive ovarian tumors showed demethylated or hypomethylated exon 1, indicating that DNA demethylation is a major epigenetic mechanism underlying aberrant SNCG expression in ovarian malignancy.","method":"RT-PCR for mRNA expression; methylation-specific PCR (MSP) of CpG island in exon 1","journal":"Neuro endocrinology letters","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single method (MSP) for methylation, single lab, correlative approach without causal perturbation of methylation","pmids":["16816827"],"is_preprint":false},{"year":2020,"finding":"SNCG promotes proliferation, migration, invasion, and tumor formation in high-grade serous ovarian cancer cells both in vitro and in vivo. Mechanistically, SNCG overexpression activates the PI3K/AKT signaling pathway, as determined by human phospho-kinase array and Western blot analysis; loss- and gain-of-function experiments confirmed that this pathway mediates the metastasis-promoting function of SNCG.","method":"Loss- and gain-of-function experiments; human phospho-kinase array; Western blot; in vitro proliferation, migration, invasion assays; in vivo tumor formation","journal":"Journal of experimental & clinical cancer research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (phospho-kinase array, Western blot, in vitro and in vivo functional assays) with both loss- and gain-of-function, single lab","pmids":["32381034"],"is_preprint":false}],"current_model":"SNCG (gamma-synuclein/persyn/BCSG1) is a small cytosolic protein of the synuclein family that is expressed in peripheral neurons (cell bodies and axons) during development, and is aberrantly overexpressed in multiple cancers via CpG island demethylation; overexpression promotes cell proliferation and tumor metastasis, at least in part through activation of the PI3K/AKT signaling pathway, and its expression in breast cancer cells is transcriptionally suppressed by oncostatin M."},"narrative":{"mechanistic_narrative":"SNCG (gamma-synuclein/persyn/BCSG1) is a small cytosolic synuclein-family protein with a dual biology: a developmentally regulated neuronal protein and an oncogenic factor aberrantly activated in epithelial cancers [PMID:9801372, PMID:9044857]. In the nervous system it localizes to the cell bodies and axons of primary sensory, sympathetic, and motor neurons from the earliest stages of axonal outgrowth, a distribution distinct from the presynaptic CNS localization of other synucleins [PMID:9801372]. SNCG was originally identified as a breast cancer-specific gene undetectable in normal breast but highly expressed in advanced infiltrating carcinoma, and tumor development correlates with overexpression of the wild-type protein rather than coding mutation [PMID:9044857, PMID:9700196]. Its aberrant expression in malignancy is driven epigenetically through CpG island hypomethylation in exon 1 [PMID:16816827] and is transcriptionally suppressed by the growth-inhibitory cytokine oncostatin M [PMID:11016747]. Functionally, SNCG acts as a pro-tumorigenic effector: gain-of-function stimulates anchorage-dependent and anchorage-independent growth [PMID:11016747], and in ovarian cancer it promotes proliferation, migration, invasion, and tumor formation in vitro and in vivo by activating PI3K/AKT signaling [PMID:32381034]. The molecular partners and biochemical activity that underlie SNCG signaling have not been resolved in the available corpus.","teleology":[{"year":1997,"claim":"Established SNCG as a cancer-associated gene by linking its expression specifically to malignant rather than normal or benign breast tissue, raising the question of its role in tumor progression.","evidence":"Differential cDNA sequencing and in situ hybridization in breast tissue","pmids":["9044857"],"confidence":"Medium","gaps":["Correlative expression only, no functional perturbation","Did not establish whether expression is cause or consequence of progression"]},{"year":1998,"claim":"Defined SNCG as a cytosolic protein of peripheral neuron cell bodies and axons, distinguishing it from other presynaptic synucleins and establishing its baseline normal biology.","evidence":"Northern, in situ hybridization, Western, and immunohistochemistry across neuronal tissues","pmids":["9801372"],"confidence":"Medium","gaps":["No functional perturbation of neuronal SNCG","Molecular role in axons not defined"]},{"year":1998,"claim":"Resolved whether tumor association arises from mutation versus overexpression by mapping the gene and screening for coding changes, showing wild-type protein overexpression drives the tumor correlation.","evidence":"Genomic cloning, chromosomal localization, mutation screening, and antibody detection in aging cortex and breast tumors","pmids":["9700196"],"confidence":"Medium","gaps":["Mechanism of overexpression not identified here","No causal test of overexpression in tumorigenesis"]},{"year":2000,"claim":"Demonstrated that SNCG is both transcriptionally controllable and functionally pro-proliferative, moving it from a marker to a candidate driver.","evidence":"Transcription-rate measurement under oncostatin M, plus stable SNCG overexpression and growth assays in MCF-7 cells","pmids":["11016747"],"confidence":"Medium","gaps":["Downstream effectors of pro-proliferative effect not defined","Single cell-line gain-of-function"]},{"year":2006,"claim":"Identified an epigenetic basis for aberrant SNCG expression, implicating CpG island hypomethylation in exon 1 in cancer-specific activation.","evidence":"RT-PCR and methylation-specific PCR of exon 1 CpG island in ovarian tumors","pmids":["16816827"],"confidence":"Low","gaps":["Correlative MSP without causal demethylation perturbation","Single method and single lab"]},{"year":2020,"claim":"Connected SNCG overexpression to a defined signaling output, showing PI3K/AKT activation mediates its metastasis-promoting function.","evidence":"Loss- and gain-of-function with phospho-kinase array, Western blot, and in vitro/in vivo assays in ovarian cancer cells","pmids":["32381034"],"confidence":"Medium","gaps":["Direct molecular partner coupling SNCG to PI3K/AKT not identified","Single lab"]},{"year":null,"claim":"The biochemical activity of SNCG and the direct binding partners that link it to PI3K/AKT activation remain unidentified.","evidence":"","pmids":[],"confidence":"Low","gaps":["No defined molecular activity or substrate","No structural model","Mechanism connecting cytosolic SNCG to receptor/kinase signaling unknown"]}],"mechanism_profile":{"molecular_activity":[],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[1]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[5]}],"complexes":[],"partners":[],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"O76070","full_name":"Gamma-synuclein","aliases":["Breast cancer-specific gene 1 protein","Persyn","Synoretin","SR"],"length_aa":127,"mass_kda":13.3,"function":"Plays a role in neurofilament network integrity. May be involved in modulating axonal architecture during development and in the adult. In vitro, increases the susceptibility of neurofilament-H to calcium-dependent proteases (By similarity). May also function in modulating the keratin network in skin. Activates the MAPK and Elk-1 signal transduction pathway (By similarity)","subcellular_location":"Cytoplasm, perinuclear region; Cytoplasm, cytoskeleton, microtubule organizing center, centrosome; Cytoplasm, cytoskeleton, spindle","url":"https://www.uniprot.org/uniprotkb/O76070/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/SNCG","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/SNCG","total_profiled":1310},"omim":[{"mim_id":"602998","title":"SYNUCLEIN, GAMMA; SNCG","url":"https://www.omim.org/entry/602998"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Golgi apparatus","reliability":"Supported"},{"location":"Centrosome","reliability":"Supported"},{"location":"Cytosol","reliability":"Supported"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"adrenal gland","ntpm":300.4},{"tissue":"blood vessel","ntpm":339.7},{"tissue":"brain","ntpm":638.1}],"url":"https://www.proteinatlas.org/search/SNCG"},"hgnc":{"alias_symbol":["BCSG1","SR","persyn"],"prev_symbol":[]},"alphafold":{"accession":"O76070","domains":[{"cath_id":"1.20.5","chopping":"10-96","consensus_level":"medium","plddt":87.0298,"start":10,"end":96}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O76070","model_url":"https://alphafold.ebi.ac.uk/files/AF-O76070-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O76070-F1-predicted_aligned_error_v6.png","plddt_mean":76.31},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=SNCG","jax_strain_url":"https://www.jax.org/strain/search?query=SNCG"},"sequence":{"accession":"O76070","fasta_url":"https://rest.uniprot.org/uniprotkb/O76070.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O76070/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O76070"}},"corpus_meta":[{"pmid":"26450910","id":"PMC_26450910","title":"Combinatorial control of Drosophila circular RNA expression by intronic repeats, hnRNPs, and SR proteins.","date":"2015","source":"Genes & development","url":"https://pubmed.ncbi.nlm.nih.gov/26450910","citation_count":415,"is_preprint":false},{"pmid":"19857271","id":"PMC_19857271","title":"The SR protein family.","date":"2009","source":"Genome biology","url":"https://pubmed.ncbi.nlm.nih.gov/19857271","citation_count":353,"is_preprint":false},{"pmid":"23525660","id":"PMC_23525660","title":"Regulation of splicing by SR proteins and SR protein-specific kinases.","date":"2013","source":"Chromosoma","url":"https://pubmed.ncbi.nlm.nih.gov/23525660","citation_count":351,"is_preprint":false},{"pmid":"21898828","id":"PMC_21898828","title":"Evolution of SR protein and hnRNP splicing regulatory factors.","date":"2011","source":"Wiley interdisciplinary reviews. 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research","url":"https://pubmed.ncbi.nlm.nih.gov/12576515","citation_count":43,"is_preprint":false},{"pmid":"19122200","id":"PMC_19122200","title":"Signalling pathway involving GULP, MAPK and Rac1 for SR-BI-induced phagocytosis of apoptotic cells.","date":"2009","source":"Journal of biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/19122200","citation_count":43,"is_preprint":false},{"pmid":"15666814","id":"PMC_15666814","title":"SR-BI and HDL cholesteryl ester metabolism.","date":"2004","source":"Endocrine research","url":"https://pubmed.ncbi.nlm.nih.gov/15666814","citation_count":42,"is_preprint":false},{"pmid":"27729859","id":"PMC_27729859","title":"Targeting SR-BI for Cancer Diagnostics, Imaging and Therapy.","date":"2016","source":"Frontiers in pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/27729859","citation_count":42,"is_preprint":false},{"pmid":"33554347","id":"PMC_33554347","title":"Noncanonical functions of the serine-arginine-rich splicing factor (SR) family of proteins in development and disease.","date":"2021","source":"BioEssays : news and reviews in molecular, cellular and developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/33554347","citation_count":40,"is_preprint":false},{"pmid":"11016747","id":"PMC_11016747","title":"Transcriptional suppression of synuclein gamma (SNCG) expression in human breast cancer cells by the growth inhibitory cytokine oncostatin M.","date":"2000","source":"Breast cancer research and treatment","url":"https://pubmed.ncbi.nlm.nih.gov/11016747","citation_count":39,"is_preprint":false},{"pmid":"9488736","id":"PMC_9488736","title":"Fission yeast mitotic regulator Dsk1 is an SR protein-specific kinase.","date":"1998","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/9488736","citation_count":39,"is_preprint":false},{"pmid":"37057625","id":"PMC_37057625","title":"Enhanced Mitochondria-SR Tethering Triggers Adaptive Cardiac Muscle Remodeling.","date":"2023","source":"Circulation research","url":"https://pubmed.ncbi.nlm.nih.gov/37057625","citation_count":37,"is_preprint":false},{"pmid":"26167880","id":"PMC_26167880","title":"SR protein kinases promote splicing of nonconsensus introns.","date":"2015","source":"Nature structural & molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/26167880","citation_count":37,"is_preprint":false},{"pmid":"24869919","id":"PMC_24869919","title":"N-terminus of the protein kinase CLK1 induces SR protein hyperphosphorylation.","date":"2014","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/24869919","citation_count":36,"is_preprint":false},{"pmid":"20574110","id":"PMC_20574110","title":"SR proteins and galectins: what's in a name?","date":"2010","source":"Glycobiology","url":"https://pubmed.ncbi.nlm.nih.gov/20574110","citation_count":36,"is_preprint":false},{"pmid":"3066491","id":"PMC_3066491","title":"SR function in malignant hyperthermia.","date":"1988","source":"Cell calcium","url":"https://pubmed.ncbi.nlm.nih.gov/3066491","citation_count":35,"is_preprint":false},{"pmid":"32974389","id":"PMC_32974389","title":"SR/RS Motifs as Critical Determinants of Coronavirus Life Cycle.","date":"2020","source":"Frontiers in molecular biosciences","url":"https://pubmed.ncbi.nlm.nih.gov/32974389","citation_count":34,"is_preprint":false},{"pmid":"29097383","id":"PMC_29097383","title":"Mind the (sr)GAP - roles of Slit-Robo GAPs in neurons, brains and beyond.","date":"2017","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/29097383","citation_count":32,"is_preprint":false},{"pmid":"31811631","id":"PMC_31811631","title":"View from an mRNP: The Roles of SR Proteins in Assembly, Maturation and Turnover.","date":"2019","source":"Advances in experimental medicine and biology","url":"https://pubmed.ncbi.nlm.nih.gov/31811631","citation_count":31,"is_preprint":false},{"pmid":"16816827","id":"PMC_16816827","title":"The role of CpG islands hypomethylation and abnormal expression of neuronal protein synuclein-gamma (SNCG) in ovarian cancer.","date":"2006","source":"Neuro endocrinology letters","url":"https://pubmed.ncbi.nlm.nih.gov/16816827","citation_count":30,"is_preprint":false},{"pmid":"32381034","id":"PMC_32381034","title":"SNCG promotes the progression and metastasis of high-grade serous ovarian cancer via targeting the PI3K/AKT signaling pathway.","date":"2020","source":"Journal of experimental & clinical cancer research : CR","url":"https://pubmed.ncbi.nlm.nih.gov/32381034","citation_count":30,"is_preprint":false},{"pmid":"33455366","id":"PMC_33455366","title":"Mechanical, Biological, and Antibacterial Characteristics of Plasma-Sprayed (Sr,Zn) Substituted Hydroxyapatite Coating.","date":"2020","source":"ACS biomaterials science & engineering","url":"https://pubmed.ncbi.nlm.nih.gov/33455366","citation_count":29,"is_preprint":false},{"pmid":"28134663","id":"PMC_28134663","title":"SR-B1 and PDZK1: partners in HDL regulation.","date":"2017","source":"Current opinion in lipidology","url":"https://pubmed.ncbi.nlm.nih.gov/28134663","citation_count":28,"is_preprint":false},{"pmid":"34940860","id":"PMC_34940860","title":"Exploring the multifunctionality of SR proteins.","date":"2022","source":"Biochemical Society transactions","url":"https://pubmed.ncbi.nlm.nih.gov/34940860","citation_count":28,"is_preprint":false},{"pmid":"36077545","id":"PMC_36077545","title":"Regulatory Network of Serine/Arginine-Rich (SR) Proteins: The Molecular Mechanism and Physiological Function in Plants.","date":"2022","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/36077545","citation_count":28,"is_preprint":false},{"pmid":"17223538","id":"PMC_17223538","title":"SR protein kinase 1 is resilient to inactivation.","date":"2007","source":"Structure (London, England : 1993)","url":"https://pubmed.ncbi.nlm.nih.gov/17223538","citation_count":28,"is_preprint":false},{"pmid":"27242666","id":"PMC_27242666","title":"ACTH Regulation of Adrenal SR-B1.","date":"2016","source":"Frontiers in endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/27242666","citation_count":27,"is_preprint":false},{"pmid":"28504304","id":"PMC_28504304","title":"Exploiting scavenger receptors in cancer immunotherapy: Lessons from CD5 and SR-B1.","date":"2017","source":"European journal of immunology","url":"https://pubmed.ncbi.nlm.nih.gov/28504304","citation_count":27,"is_preprint":false},{"pmid":"11526235","id":"PMC_11526235","title":"Regulation of SR protein localization during development.","date":"2001","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/11526235","citation_count":27,"is_preprint":false},{"pmid":"37098235","id":"PMC_37098235","title":"The SCL30a SR protein regulates ABA-dependent seed traits and germination under stress.","date":"2023","source":"Plant, cell & environment","url":"https://pubmed.ncbi.nlm.nih.gov/37098235","citation_count":24,"is_preprint":false},{"pmid":"31119270","id":"PMC_31119270","title":"Targeted invalidation of SR-B1 in macrophages reduces macrophage apoptosis and accelerates atherosclerosis.","date":"2020","source":"Cardiovascular research","url":"https://pubmed.ncbi.nlm.nih.gov/31119270","citation_count":24,"is_preprint":false},{"pmid":"17076265","id":"PMC_17076265","title":"SR proteins as potential targets for therapy.","date":"2006","source":"Progress in molecular and subcellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/17076265","citation_count":23,"is_preprint":false},{"pmid":"21327085","id":"PMC_21327085","title":"SR and SR-related proteins redistribute to segregated fibrillar components of nucleoli in a response to DNA damage.","date":"2010","source":"Nucleus (Austin, Tex.)","url":"https://pubmed.ncbi.nlm.nih.gov/21327085","citation_count":23,"is_preprint":false},{"pmid":"20525644","id":"PMC_20525644","title":"Mitochondrial uncoupling downregulates calsequestrin expression and reduces SR Ca2+ stores in cardiomyocytes.","date":"2010","source":"Cardiovascular research","url":"https://pubmed.ncbi.nlm.nih.gov/20525644","citation_count":23,"is_preprint":false},{"pmid":"31275377","id":"PMC_31275377","title":"The SR-B1 Receptor as a Potential Target for Treating Glioblastoma.","date":"2019","source":"Journal of oncology","url":"https://pubmed.ncbi.nlm.nih.gov/31275377","citation_count":22,"is_preprint":false},{"pmid":"8951564","id":"PMC_8951564","title":"SR Ca(2+)-ATPase/phospholamban in cardiomyocyte function.","date":"1996","source":"Journal of cardiac failure","url":"https://pubmed.ncbi.nlm.nih.gov/8951564","citation_count":22,"is_preprint":false},{"pmid":"28576472","id":"PMC_28576472","title":"Redirecting SR Protein Nuclear Trafficking through an Allosteric Platform.","date":"2017","source":"Journal of molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/28576472","citation_count":22,"is_preprint":false},{"pmid":"22140111","id":"PMC_22140111","title":"The structure and selectivity of the SR protein SRSF2 RRM domain with RNA.","date":"2011","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/22140111","citation_count":22,"is_preprint":false},{"pmid":"25400739","id":"PMC_25400739","title":"Expression of SNCG, MAP2, SDF-1 and CXCR4 in gastric adenocarcinoma and their clinical significance.","date":"2014","source":"International journal of clinical and experimental pathology","url":"https://pubmed.ncbi.nlm.nih.gov/25400739","citation_count":21,"is_preprint":false},{"pmid":"33854493","id":"PMC_33854493","title":"Interplay Between CMGC Kinases Targeting SR Proteins and Viral Replication: Splicing and Beyond.","date":"2021","source":"Frontiers in microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/33854493","citation_count":21,"is_preprint":false},{"pmid":"31935456","id":"PMC_31935456","title":"SR-BI as a target of natural products and its significance in cancer.","date":"2020","source":"Seminars in cancer biology","url":"https://pubmed.ncbi.nlm.nih.gov/31935456","citation_count":20,"is_preprint":false},{"pmid":"21600902","id":"PMC_21600902","title":"Regulating SR protein phosphorylation through regions outside the kinase domain of SRPK1.","date":"2011","source":"Journal of molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/21600902","citation_count":20,"is_preprint":false},{"pmid":"30519876","id":"PMC_30519876","title":"Significance of Cholesterol-Binding Motifs in ABCA1, ABCG1, and SR-B1 Structure.","date":"2018","source":"The Journal of membrane biology","url":"https://pubmed.ncbi.nlm.nih.gov/30519876","citation_count":20,"is_preprint":false},{"pmid":"38778254","id":"PMC_38778254","title":"SR proteins in cancer: function, regulation, and small inhibitor.","date":"2024","source":"Cellular & molecular biology letters","url":"https://pubmed.ncbi.nlm.nih.gov/38778254","citation_count":19,"is_preprint":false},{"pmid":"36131558","id":"PMC_36131558","title":"Insights into established and emerging roles of SR protein family in plants and animals.","date":"2022","source":"Wiley interdisciplinary reviews. RNA","url":"https://pubmed.ncbi.nlm.nih.gov/36131558","citation_count":19,"is_preprint":false},{"pmid":"20659014","id":"PMC_20659014","title":"Human papillomavirus regulation of SR proteins.","date":"2010","source":"Biochemical Society transactions","url":"https://pubmed.ncbi.nlm.nih.gov/20659014","citation_count":18,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":43461,"output_tokens":2112,"usd":0.081032,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8515,"output_tokens":1982,"usd":0.046062,"stage2_stop_reason":"end_turn"},"total_usd":0.127094,"stage1_batch_id":"msgbatch_013LWZZT6MWaqB9qyTSeQBmU","stage2_batch_id":"msgbatch_0194ZzQaTGNpruoNJBbEMbt3","note":"batch pricing = 50% of standard"},"stage1_raw":"Looking through the abstracts, I need to identify papers about the canonical SNCG protein (gamma-synuclein, also known as BCSG1 or persyn). \n\nThe vast majority of papers (1-4, 7-8, 12-15, 17-22, 24, 26, 28-32, etc.) are about SR splicing factor proteins — a completely different gene family. \"SR\" in these contexts stands for serine/arginine-rich splicing factors, not SNCG.\n\nPapers 5-6, 10, 16, 23, 29, 35-36, 42, 45, 50, 52-54, 57, 59-62, 81-82, 85, 89, 95, 97 are about SR-BI (scavenger receptor class B type I / SCARB1) — also a different gene.\n\nPapers specifically about SNCG (gamma-synuclein/persyn/BCSG1):\n- PMID:9044857 [9] - BCSG1 identification in breast cancer\n- PMID:9801372 [25] - persyn characterization in nervous system\n- PMID:9700196 [33] - human persyn gene organization\n- PMID:11016747 [64] - SNCG transcriptional regulation by oncostatin M\n- PMID:19706805 [41] - SNCG in colorectal cancer metastasis\n- PMID:16816827 [74] - SNCG methylation in ovarian cancer\n- PMID:32381034 [75] - SNCG and PI3K/AKT in ovarian cancer\n- PMID:25400739 [93] - SNCG expression in gastric cancer\n\n```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1997,\n      \"finding\": \"BCSG1 (SNCG) was identified as a breast cancer-specific gene whose predicted amino acid sequence has significant homology to the non-amyloid beta protein fragment of the Alzheimer's disease amyloid protein. In situ hybridization showed BCSG1 is undetectable in normal or benign breast lesions but expressed at high levels in advanced infiltrating breast cancer, suggesting a role in malignant progression.\",\n      \"method\": \"Direct differential cDNA sequencing; in situ hybridization\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — original identification by cDNA sequencing and in situ hybridization in a single study; provides structural homology and expression context but limited mechanistic follow-up\",\n      \"pmids\": [\"9044857\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Persyn (SNCG) is a cytosolic protein expressed predominantly in cell bodies and axons of primary sensory neurons, sympathetic neurons, and motoneurons — in contrast to other synucleins, which are presynaptic proteins of CNS neurons. Expression begins from the earliest stages of axonal outgrowth and is maintained throughout life. Persyn also becomes detectable in evolutionary recent brain regions by adulthood.\",\n      \"method\": \"Northern blotting, in situ hybridization, Western blotting, immunohistochemistry\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — multiple orthogonal methods (Northern, ISH, Western, IHC) establishing distinct subcellular localization in a single study; no functional perturbation experiment\",\n      \"pmids\": [\"9801372\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"The human persyn (SNCG) gene was localized to chromosome 10q23.2-q23.3. Antibody-based detection showed increased persyn protein levels in ageing cerebral cortex and in breast tumors. No tumor-specific coding mutations were found, but two linked coding-region polymorphisms were identified, suggesting that breast tumor development correlates with overexpression of the wild-type persyn protein rather than mutation.\",\n      \"method\": \"Antibody immunodetection (Western blot/IHC), genomic cloning and sequencing, chromosomal localization, mutation screening by sequencing\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — chromosomal localization and protein-level detection with specific antibody; mutation screen provides mechanistic exclusion of coding mutation as driver\",\n      \"pmids\": [\"9700196\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"SNCG mRNA expression in breast cancer cells is transcriptionally suppressed by the growth-inhibitory cytokine oncostatin M (OM), with suppression detectable within 30 min and mRNA below detectable levels by 24 h. Pulse-chase transcription rate measurements confirmed the effect occurs mainly at the transcriptional level. Stable overexpression of SNCG cDNA in MCF-7 cells (which lack endogenous SNCG) significantly stimulated anchorage-dependent and anchorage-independent cell growth, demonstrating a pro-proliferative role for SNCG.\",\n      \"method\": \"Transcriptional rate measurement; Western blot; stable transfection with SNCG cDNA; anchorage-dependent and soft-agar growth assays\",\n      \"journal\": \"Breast cancer research and treatment\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — multiple complementary methods (transcription rate, protein expression, functional gain-of-function growth assay) in a single study; establishes transcriptional regulation and pro-proliferative function\",\n      \"pmids\": [\"11016747\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Abnormal SNCG expression in ovarian cancer is associated with CpG island hypomethylation in exon 1 of the SNCG gene; 75.7% of SNCG mRNA-positive ovarian tumors showed demethylated or hypomethylated exon 1, indicating that DNA demethylation is a major epigenetic mechanism underlying aberrant SNCG expression in ovarian malignancy.\",\n      \"method\": \"RT-PCR for mRNA expression; methylation-specific PCR (MSP) of CpG island in exon 1\",\n      \"journal\": \"Neuro endocrinology letters\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single method (MSP) for methylation, single lab, correlative approach without causal perturbation of methylation\",\n      \"pmids\": [\"16816827\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"SNCG promotes proliferation, migration, invasion, and tumor formation in high-grade serous ovarian cancer cells both in vitro and in vivo. Mechanistically, SNCG overexpression activates the PI3K/AKT signaling pathway, as determined by human phospho-kinase array and Western blot analysis; loss- and gain-of-function experiments confirmed that this pathway mediates the metastasis-promoting function of SNCG.\",\n      \"method\": \"Loss- and gain-of-function experiments; human phospho-kinase array; Western blot; in vitro proliferation, migration, invasion assays; in vivo tumor formation\",\n      \"journal\": \"Journal of experimental & clinical cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (phospho-kinase array, Western blot, in vitro and in vivo functional assays) with both loss- and gain-of-function, single lab\",\n      \"pmids\": [\"32381034\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"SNCG (gamma-synuclein/persyn/BCSG1) is a small cytosolic protein of the synuclein family that is expressed in peripheral neurons (cell bodies and axons) during development, and is aberrantly overexpressed in multiple cancers via CpG island demethylation; overexpression promotes cell proliferation and tumor metastasis, at least in part through activation of the PI3K/AKT signaling pathway, and its expression in breast cancer cells is transcriptionally suppressed by oncostatin M.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"SNCG (gamma-synuclein/persyn/BCSG1) is a small cytosolic synuclein-family protein with a dual biology: a developmentally regulated neuronal protein and an oncogenic factor aberrantly activated in epithelial cancers [#1, #0]. In the nervous system it localizes to the cell bodies and axons of primary sensory, sympathetic, and motor neurons from the earliest stages of axonal outgrowth, a distribution distinct from the presynaptic CNS localization of other synucleins [#1]. SNCG was originally identified as a breast cancer-specific gene undetectable in normal breast but highly expressed in advanced infiltrating carcinoma, and tumor development correlates with overexpression of the wild-type protein rather than coding mutation [#0, #2]. Its aberrant expression in malignancy is driven epigenetically through CpG island hypomethylation in exon 1 [#4] and is transcriptionally suppressed by the growth-inhibitory cytokine oncostatin M [#3]. Functionally, SNCG acts as a pro-tumorigenic effector: gain-of-function stimulates anchorage-dependent and anchorage-independent growth [#3], and in ovarian cancer it promotes proliferation, migration, invasion, and tumor formation in vitro and in vivo by activating PI3K/AKT signaling [#5]. The molecular partners and biochemical activity that underlie SNCG signaling have not been resolved in the available corpus.\",\n  \"teleology\": [\n    {\n      \"year\": 1997,\n      \"claim\": \"Established SNCG as a cancer-associated gene by linking its expression specifically to malignant rather than normal or benign breast tissue, raising the question of its role in tumor progression.\",\n      \"evidence\": \"Differential cDNA sequencing and in situ hybridization in breast tissue\",\n      \"pmids\": [\"9044857\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Correlative expression only, no functional perturbation\", \"Did not establish whether expression is cause or consequence of progression\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Defined SNCG as a cytosolic protein of peripheral neuron cell bodies and axons, distinguishing it from other presynaptic synucleins and establishing its baseline normal biology.\",\n      \"evidence\": \"Northern, in situ hybridization, Western, and immunohistochemistry across neuronal tissues\",\n      \"pmids\": [\"9801372\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No functional perturbation of neuronal SNCG\", \"Molecular role in axons not defined\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Resolved whether tumor association arises from mutation versus overexpression by mapping the gene and screening for coding changes, showing wild-type protein overexpression drives the tumor correlation.\",\n      \"evidence\": \"Genomic cloning, chromosomal localization, mutation screening, and antibody detection in aging cortex and breast tumors\",\n      \"pmids\": [\"9700196\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism of overexpression not identified here\", \"No causal test of overexpression in tumorigenesis\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Demonstrated that SNCG is both transcriptionally controllable and functionally pro-proliferative, moving it from a marker to a candidate driver.\",\n      \"evidence\": \"Transcription-rate measurement under oncostatin M, plus stable SNCG overexpression and growth assays in MCF-7 cells\",\n      \"pmids\": [\"11016747\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Downstream effectors of pro-proliferative effect not defined\", \"Single cell-line gain-of-function\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Identified an epigenetic basis for aberrant SNCG expression, implicating CpG island hypomethylation in exon 1 in cancer-specific activation.\",\n      \"evidence\": \"RT-PCR and methylation-specific PCR of exon 1 CpG island in ovarian tumors\",\n      \"pmids\": [\"16816827\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Correlative MSP without causal demethylation perturbation\", \"Single method and single lab\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Connected SNCG overexpression to a defined signaling output, showing PI3K/AKT activation mediates its metastasis-promoting function.\",\n      \"evidence\": \"Loss- and gain-of-function with phospho-kinase array, Western blot, and in vitro/in vivo assays in ovarian cancer cells\",\n      \"pmids\": [\"32381034\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct molecular partner coupling SNCG to PI3K/AKT not identified\", \"Single lab\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The biochemical activity of SNCG and the direct binding partners that link it to PI3K/AKT activation remain unidentified.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No defined molecular activity or substrate\", \"No structural model\", \"Mechanism connecting cytosolic SNCG to receptor/kinase signaling unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [5]}\n    ],\n    \"complexes\": [],\n    \"partners\": [],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}