{"gene":"SH2D1B","run_date":"2026-04-28T20:42:07","timeline":{"discoveries":[{"year":2001,"finding":"EAT-2 (SH2D1B) is a free SH2 domain protein expressed in macrophages and B lymphocytes that binds phosphorylated SLAM family receptors (CD84, CD150/SLAM, CD229, CD244) via a pTyr motif, and acts as a natural inhibitor by interfering with recruitment of the tyrosine phosphatase SHP-2 to these receptors. Unlike SAP, EAT-2 does not bind non-phosphorylated CD150.","method":"Crystal structure of EAT-2 in complex with phosphotyrosine peptide from CD150 cytoplasmic tail; biochemical binding assays; competition assays with SHP-2","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 1 — crystal structure plus biochemical binding and functional assays in a single study","pmids":["11689425"],"is_preprint":false},{"year":2005,"finding":"EAT-2 associates with the SLAM-related receptor 2B4 in NK cells and inhibits NK cell natural cytotoxicity and IFN-γ secretion by a mechanism requiring tyrosine phosphorylation of its C-terminal tail. The related adaptor ERT shares this inhibitory function.","method":"EAT-2-deficient and EAT-2-overexpressing mouse models; co-immunoprecipitation; functional cytotoxicity and cytokine assays; phosphorylation studies with tyrosine mutants","journal":"Nature immunology","confidence":"High","confidence_rationale":"Tier 2 — genetic KO/OE mice plus biochemical and functional assays, strong and replicated","pmids":["16127454"],"is_preprint":false},{"year":2005,"finding":"Upon activation, CRACC associates with EAT-2 in human NK cells; EAT-2 association induces CRACC tyrosine phosphorylation partially dependent on Src kinases, and downstream signals include PLCγ1, PLCγ2, and PI3K activation leading to NK cell cytotoxicity. EAT-2 also associates with 2B4 predominantly in resting NK cells.","method":"Co-immunoprecipitation; pharmacological Src kinase inhibition; functional cytotoxicity assays; signaling pathway analysis","journal":"Journal of immunology","confidence":"High","confidence_rationale":"Tier 2 — reciprocal Co-IP plus pathway dissection with inhibitors and functional readouts","pmids":["16339536"],"is_preprint":false},{"year":2006,"finding":"EAT-2 is recruited specifically to the second tyrosine (in an ITSM motif) of NTB-A in human NK cells; this recruitment mediates NTB-A-dependent cytotoxicity but not IFN-γ production, demonstrating differential dependence on EAT-2 versus SAP for distinct NK cell effector functions.","method":"NTB-A tyrosine mutants expressed in NTB-A-negative NK cell line; SAP silencing by siRNA; functional cytotoxicity and cytokine assays","journal":"Journal of immunology","confidence":"High","confidence_rationale":"Tier 2 — site-directed mutagenesis plus KD with clear functional separation of two effector outputs","pmids":["16920955"],"is_preprint":false},{"year":2009,"finding":"CRACC positively regulates NK cell function through EAT-2 (but not SAP); in the absence of EAT-2, CRACC becomes inhibitory. In T cells, which lack EAT-2, CRACC is inhibitory. Thus EAT-2 availability determines the activating vs. inhibitory outcome of CRACC signaling.","method":"CRACC-deficient mouse; EAT-2-deficient mouse; genetic epistasis; NK cell functional assays (cytotoxicity, cytokine production)","journal":"Nature immunology","confidence":"High","confidence_rationale":"Tier 2 — genetic epistasis with two KO mouse models and clear phenotypic rescue logic","pmids":["19151721"],"is_preprint":false},{"year":2014,"finding":"EAT-2 mediates NK cell activation by linking SLAM family receptors to PLCγ, calcium flux, and Erk kinase signaling via one or two tyrosines in its C-terminal tail (not found in SAP). Unlike SAP, EAT-2 does not enhance NK–target conjugate formation but instead accelerates polarization and exocytosis of cytotoxic granules toward hematopoietic target cells.","method":"Genetic, biochemical (phosphorylation, co-IP), and live-imaging approaches; EAT-2 tyrosine mutants; calcium flux assays; Erk activation assays; granule polarization imaging","journal":"The Journal of experimental medicine","confidence":"High","confidence_rationale":"Tier 1–2 — multiple orthogonal methods including mutagenesis, biochemistry, and live imaging in a single rigorous study","pmids":["24687958"],"is_preprint":false},{"year":2002,"finding":"CD84, upon ligation, undergoes rapid tyrosine phosphorylation and recruits both SAP and EAT-2, suggesting EAT-2 participates in signal transduction through this SLAM family receptor on B cells.","method":"Co-immunoprecipitation of SAP and EAT-2 with phosphorylated CD84; anti-CD84 antibody ligation assays on primary human B cells","journal":"European journal of immunology","confidence":"Medium","confidence_rationale":"Tier 3 — single Co-IP demonstration on primary cells, no mechanistic follow-up","pmids":["12115647"],"is_preprint":false},{"year":2015,"finding":"EAT-2 negatively regulates cytokine (IL-12) production in dendritic cells downstream of SLAM engagement by blocking activation of p38 MAPK and JNK signaling pathways following CD40 cross-linking; a NZB mouse promoter polymorphism reducing EAT-2 expression by ~70% in DCs disrupts this inhibition and promotes lupus-like autoimmunity.","method":"EAT-2 gene silencing in DCs; downstream signaling analysis (p38, JNK); T cell–DC co-culture assays; subcongenic mouse mapping","journal":"Journal of immunology","confidence":"Medium","confidence_rationale":"Tier 2 — genetic reduction plus signaling pathway analysis, single lab","pmids":["26432891"],"is_preprint":false},{"year":2016,"finding":"The crystal structure of human EAT-2 (SH2D1B) in unliganded form reveals conformational differences in ligand-binding loops compared with mouse EAT-2–peptide complex structure, and shows similar calculated binding energies to unphosphorylated ligands as SAP, suggesting additional factors beyond the SH2 domain contribute to the differential phosphotyrosine specificity of EAT-2 versus SAP.","method":"X-ray crystallography of human EAT-2; structural comparison with mouse EAT-2 and SAP","journal":"Protein and peptide letters","confidence":"Medium","confidence_rationale":"Tier 1 — crystal structure, but limited functional validation; single study","pmids":["27586300"],"is_preprint":false},{"year":1996,"finding":"EAT-2 (SH2D1B) was identified as a novel gene upregulated by the EWS/FLI1 fusion oncogene; it encodes a protein containing a biochemically functional SH2 domain and its expression correlates with EWS/FLI1-mediated transformation of NIH3T3 cells.","method":"Representational difference analysis (RDA); RT-PCR; SH2 domain functional assessment; NIH3T3 transformation assay","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 3 — original identification with biochemical SH2 activity and transformation correlation, single lab","pmids":["9000139"],"is_preprint":false},{"year":2013,"finding":"EAT-2 overexpression enhances human NK cell anti-tumor activity, DC maturation, and monocyte phagocytosis; these effects are abolished by an R31Q mutation in the SH2 domain, indicating the interaction between EAT-2 and SLAM receptors (via its SH2 domain) is required for these immunomodulatory functions.","method":"EAT-2 overexpression in human PBMCs; R31Q SH2 mutant as negative control; NK cytotoxicity assays; DC maturation assays; phagocytosis assays","journal":"International immunology","confidence":"Medium","confidence_rationale":"Tier 2–3 — functional assays with SH2-domain mutant control demonstrating domain requirement, single lab","pmids":["24374770"],"is_preprint":false}],"current_model":"SH2D1B (EAT-2) is a free SH2 domain adaptor expressed in innate immune cells (NK cells, macrophages, dendritic cells, B cells) that binds phosphorylated tyrosine motifs (ITSMs) in the cytoplasmic tails of SLAM family receptors (2B4, CRACC, NTB-A, CD84, CD150, CD229, CD244), and depending on cellular context either activates NK cells by coupling these receptors to PLCγ, calcium flux, Erk, and cytotoxic granule polarization via tyrosines in its unique C-terminal tail, or inhibits signaling (e.g., blocking SHP-2 recruitment or suppressing p38/JNK in DCs), with the net outcome determined by the availability of EAT-2 itself as a competing effector relative to the inhibitory machinery."},"narrative":{"teleology":[{"year":1996,"claim":"Before its immune function was recognized, EAT-2 was identified as a novel SH2-domain-containing gene upregulated by the EWS/FLI1 oncogene, establishing that it encodes a functional SH2 domain protein.","evidence":"Representational difference analysis and SH2 domain functional assays in NIH3T3 cells transformed by EWS/FLI1","pmids":["9000139"],"confidence":"Medium","gaps":["No immune cell context examined","Physiological target ligands unknown","Transformation correlation not mechanistically resolved"]},{"year":2001,"claim":"Structural and biochemical work revealed that EAT-2 binds phosphorylated (but not unphosphorylated) SLAM family receptor ITSMs and competes with SHP-2, establishing its mechanism as a natural inhibitor of phosphatase-mediated signaling at these receptors.","evidence":"Crystal structure of EAT-2 bound to phosphotyrosine peptide from CD150; competition assays with SHP-2","pmids":["11689425"],"confidence":"High","gaps":["Functional consequence of SHP-2 displacement not tested in living immune cells","Whether EAT-2 also transmits positive signals was unknown"]},{"year":2002,"claim":"Demonstration that CD84 ligation recruits EAT-2 in primary B cells extended the receptor repertoire for EAT-2 beyond CD150.","evidence":"Co-immunoprecipitation of EAT-2 with tyrosine-phosphorylated CD84 in human B cells","pmids":["12115647"],"confidence":"Medium","gaps":["No reciprocal IP or mutagenesis","Downstream signaling not characterized","Functional consequence in B cells not tested"]},{"year":2005,"claim":"Genetic studies in mice and human NK cells showed that EAT-2 both inhibits 2B4-mediated NK cytotoxicity (via its C-terminal tyrosines) and activates CRACC-dependent NK killing (via PLCγ/PI3K), revealing that EAT-2 is not a simple inhibitor but a context-dependent signaling switch.","evidence":"EAT-2-knockout and overexpression mouse models; co-IP; cytotoxicity and IFN-γ assays; Src kinase inhibition; tyrosine-to-phenylalanine mutants","pmids":["16127454","16339536"],"confidence":"High","gaps":["How EAT-2 exerts opposite effects through different SLAM receptors was unresolved","Downstream signaling cascade beyond PLCγ/PI3K not fully mapped"]},{"year":2006,"claim":"Mapping of EAT-2 recruitment to the second ITSM tyrosine of NTB-A showed receptor-site specificity and demonstrated that EAT-2 selectively mediates cytotoxicity but not IFN-γ production through NTB-A, establishing functional compartmentalization between EAT-2 and SAP.","evidence":"NTB-A tyrosine mutants in an NTB-A-negative NK line; SAP siRNA knockdown; cytotoxicity and cytokine assays","pmids":["16920955"],"confidence":"High","gaps":["Structural basis for ITSM selectivity not resolved","Mechanism coupling EAT-2 to granule release versus cytokine pathways unknown"]},{"year":2009,"claim":"Genetic epistasis between CRACC-KO and EAT-2-KO mice proved that EAT-2 availability is the molecular switch determining whether CRACC activates or inhibits NK cells, explaining why CRACC is inhibitory in T cells that lack EAT-2.","evidence":"CRACC-deficient and EAT-2-deficient mouse crosses; NK functional assays","pmids":["19151721"],"confidence":"High","gaps":["Identity of the inhibitory effector recruited in the absence of EAT-2 not defined","Whether this switch operates for all SLAM receptors was untested"]},{"year":2013,"claim":"An SH2-domain-disrupting R31Q mutation abolished EAT-2-mediated enhancement of NK cytotoxicity, DC maturation, and monocyte phagocytosis, confirming that SLAM receptor binding through the SH2 domain is essential for all tested immunomodulatory functions.","evidence":"EAT-2 and R31Q mutant overexpression in human PBMCs; NK, DC, and phagocytosis functional assays","pmids":["24374770"],"confidence":"Medium","gaps":["Overexpression system; endogenous levels not tested","Precise receptor targets mediating DC and monocyte effects not identified"]},{"year":2014,"claim":"Detailed dissection showed that C-terminal tail tyrosines of EAT-2 couple SLAM receptors to PLCγ, calcium, and Erk to drive cytotoxic granule polarization and exocytosis — a mechanism distinct from SAP, which promotes conjugate formation — thereby defining the unique effector arm of EAT-2 in NK cell killing.","evidence":"EAT-2 tyrosine mutants; calcium flux; Erk activation; live imaging of granule polarization","pmids":["24687958"],"confidence":"High","gaps":["Whether EAT-2 directly recruits PLCγ or acts through an intermediate kinase not resolved","Contribution of individual tail tyrosines not fully dissected"]},{"year":2015,"claim":"EAT-2 was shown to function as a negative regulator in dendritic cells by suppressing p38 and JNK downstream of SLAM/CD40, restraining IL-12; a natural NZB promoter polymorphism reducing EAT-2 expression leads to enhanced DC activation and lupus-like autoimmunity.","evidence":"Gene silencing in DCs; signaling analysis; T cell–DC co-culture; subcongenic NZB mouse mapping","pmids":["26432891"],"confidence":"Medium","gaps":["Mechanism by which EAT-2 blocks p38/JNK not defined","Whether the NZB polymorphism is causal or linked requires further genetic dissection","Inhibitory versus activating function in DCs vs NK cells not mechanistically reconciled"]},{"year":null,"claim":"The molecular basis for how EAT-2 switches between activating (NK cell) and inhibitory (DC, T cell) outputs at different SLAM receptors remains unresolved, and no direct structural view of the EAT-2 C-terminal tail engaged with PLCγ or other effectors exists.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structure of EAT-2 tail bound to PLCγ or downstream effectors","Whether EAT-2 recruits PLCγ directly or via an adaptor is unknown","Cell-type-specific co-factors that determine activating versus inhibitory outcome not identified"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,1,2,3,5]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[0,5]}],"pathway":[{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[1,2,3,4,5,7,10]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,2,5,7]}],"complexes":[],"partners":["CD244","SLAMF7","SLAMF6","CD84","SLAMF1","SLAMF3","PLCG1","PTPN11"],"other_free_text":[]},"mechanistic_narrative":"SH2D1B (EAT-2) is a free SH2 domain adaptor protein that transduces signals from SLAM family receptors to control innate immune cell activation and inhibition. EAT-2 binds phosphorylated ITSM motifs in the cytoplasmic tails of SLAM family receptors (CD150, CD84, CD229, CD244/2B4, CRACC, NTB-A), competing with the phosphatase SHP-2 for receptor access and thereby modulating downstream signaling outcomes [PMID:11689425, PMID:12115647, PMID:16920955]. In NK cells, EAT-2 couples SLAM family receptors to PLCγ, calcium flux, and Erk activation through tyrosine residues in its unique C-terminal tail, promoting cytotoxic granule polarization and exocytosis toward hematopoietic targets; in the absence of EAT-2, receptors such as CRACC switch from activating to inhibitory [PMID:24687958, PMID:19151721, PMID:16339536]. In dendritic cells, EAT-2 instead functions as a negative regulator by suppressing p38 MAPK and JNK signaling downstream of SLAM engagement, restraining IL-12 production, and a promoter polymorphism reducing EAT-2 expression in NZB mice promotes lupus-like autoimmunity [PMID:26432891]."},"prefetch_data":{"uniprot":{"accession":"O14796","full_name":"SH2 domain-containing protein 1B","aliases":["EWS/FLI1-activated transcript 2","EAT-2"],"length_aa":132,"mass_kda":15.3,"function":"Cytoplasmic adapter regulating receptors of the signaling lymphocytic activation molecule (SLAM) family such as CD84, SLAMF1, LY9 and CD244 (PubMed:11689425). In SLAM signaling seems to cooperate with SH2D1A/SAP. Plays a role in regulation of effector functions of natural killer (NK) cells by controlling signal transduction through CD244/2B4 without effecting its tyrosine phosphorylation; downstream signaling involves PLCG1 and ERK activation (PubMed:24687958). Activation of SLAMF7-mediated NK cell function does not effect receptor tyrosine phosphorylation but distal signaling (By similarity). In the context of NK cell-mediated cytotoxicity does not enhance conjugate formation with target cells but stimulates polarization of the microtubule-organizing center and cytotoxic granules toward the NK cell synapse (PubMed:24687958). Negatively regulates CD40-induced cytokine production in dendritic cells downstream of SLAM family receptors probably by inducing activation of the PI3K pathway to inhibit p38 MAPK and JNK activation (By similarity)","subcellular_location":"","url":"https://www.uniprot.org/uniprotkb/O14796/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/SH2D1B","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/SH2D1B","total_profiled":1310},"omim":[{"mim_id":"608510","title":"SH2 DOMAIN-CONTAINING 1B; SH2D1B","url":"https://www.omim.org/entry/608510"},{"mim_id":"606625","title":"SLAM FAMILY, MEMBER 7; SLAMF7","url":"https://www.omim.org/entry/606625"},{"mim_id":"600684","title":"T-LYMPHOCYTE SURFACE ANTIGEN LY-9; LY9","url":"https://www.omim.org/entry/600684"},{"mim_id":"152700","title":"SYSTEMIC LUPUS ERYTHEMATOSUS; SLE","url":"https://www.omim.org/entry/152700"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"lymphoid tissue","ntpm":7.1},{"tissue":"skeletal muscle","ntpm":11.4},{"tissue":"tongue","ntpm":6.1}],"url":"https://www.proteinatlas.org/search/SH2D1B"},"hgnc":{"alias_symbol":["EAT2"],"prev_symbol":[]},"alphafold":{"accession":"O14796","domains":[{"cath_id":"3.30.505.10","chopping":"13-101","consensus_level":"high","plddt":92.1838,"start":13,"end":101}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O14796","model_url":"https://alphafold.ebi.ac.uk/files/AF-O14796-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O14796-F1-predicted_aligned_error_v6.png","plddt_mean":80.25},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=SH2D1B","jax_strain_url":"https://www.jax.org/strain/search?query=SH2D1B"},"sequence":{"accession":"O14796","fasta_url":"https://rest.uniprot.org/uniprotkb/O14796.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O14796/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O14796"}},"corpus_meta":[{"pmid":"19151721","id":"PMC_19151721","title":"Influence of CRACC, a SLAM family receptor coupled to the adaptor EAT-2, on natural killer cell function.","date":"2009","source":"Nature immunology","url":"https://pubmed.ncbi.nlm.nih.gov/19151721","citation_count":147,"is_preprint":false},{"pmid":"15020415","id":"PMC_15020415","title":"eat-2 and eat-18 are required for nicotinic neurotransmission in the Caenorhabditis elegans pharynx.","date":"2004","source":"Genetics","url":"https://pubmed.ncbi.nlm.nih.gov/15020415","citation_count":138,"is_preprint":false},{"pmid":"16127454","id":"PMC_16127454","title":"Negative regulation of natural killer cell function by EAT-2, a SAP-related adaptor.","date":"2005","source":"Nature immunology","url":"https://pubmed.ncbi.nlm.nih.gov/16127454","citation_count":117,"is_preprint":false},{"pmid":"11689425","id":"PMC_11689425","title":"Structural basis for the interaction of the free SH2 domain EAT-2 with SLAM receptors in hematopoietic cells.","date":"2001","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/11689425","citation_count":116,"is_preprint":false},{"pmid":"16339536","id":"PMC_16339536","title":"The cytotoxicity receptor CRACC (CS-1) recruits EAT-2 and activates the PI3K and phospholipase Cgamma signaling pathways in human NK cells.","date":"2005","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/16339536","citation_count":105,"is_preprint":false},{"pmid":"9000139","id":"PMC_9000139","title":"EAT-2 is a novel SH2 domain containing protein that is up regulated by Ewing's sarcoma EWS/FLI1 fusion gene.","date":"1996","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/9000139","citation_count":88,"is_preprint":false},{"pmid":"24687958","id":"PMC_24687958","title":"EAT-2, a SAP-like adaptor, controls NK cell activation through phospholipase Cγ, Ca++, and Erk, leading to granule polarization.","date":"2014","source":"The Journal of experimental medicine","url":"https://pubmed.ncbi.nlm.nih.gov/24687958","citation_count":79,"is_preprint":false},{"pmid":"12115647","id":"PMC_12115647","title":"CD84 is up-regulated on a major population of human memory B cells and recruits the SH2 domain containing proteins SAP and EAT-2.","date":"2002","source":"European journal of immunology","url":"https://pubmed.ncbi.nlm.nih.gov/12115647","citation_count":73,"is_preprint":false},{"pmid":"16920955","id":"PMC_16920955","title":"Molecular analysis of NTB-A signaling: a role for EAT-2 in NTB-A-mediated activation of human NK cells.","date":"2006","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/16920955","citation_count":43,"is_preprint":false},{"pmid":"32566245","id":"PMC_32566245","title":"Lifespan and healthspan benefits of exogenous H2S in C. elegans are independent from effects downstream of eat-2 mutation.","date":"2020","source":"NPJ aging and mechanisms of disease","url":"https://pubmed.ncbi.nlm.nih.gov/32566245","citation_count":34,"is_preprint":false},{"pmid":"21149608","id":"PMC_21149608","title":"Expression of the SLAM family of receptors adapter EAT-2 as a novel strategy for enhancing beneficial immune responses to vaccine antigens.","date":"2010","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/21149608","citation_count":31,"is_preprint":false},{"pmid":"32243475","id":"PMC_32243475","title":"EAT-18 is an essential auxiliary protein interacting with the non-alpha nAChR subunit EAT-2 to form a functional receptor.","date":"2020","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/32243475","citation_count":14,"is_preprint":false},{"pmid":"22745373","id":"PMC_22745373","title":"Vaccines expressing the innate immune modulator EAT-2 elicit potent effector memory T lymphocyte responses despite pre-existing vaccine immunity.","date":"2012","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/22745373","citation_count":14,"is_preprint":false},{"pmid":"24374770","id":"PMC_24374770","title":"Manipulation of EAT-2 expression promotes induction of multiple beneficial regulatory and effector functions of the human innate immune system as a novel immunomodulatory strategy.","date":"2013","source":"International immunology","url":"https://pubmed.ncbi.nlm.nih.gov/24374770","citation_count":13,"is_preprint":false},{"pmid":"21912619","id":"PMC_21912619","title":"Vaccine platforms combining circumsporozoite protein and potent immune modulators, rEA or EAT-2, paradoxically result in opposing immune responses.","date":"2011","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/21912619","citation_count":12,"is_preprint":false},{"pmid":"23949283","id":"PMC_23949283","title":"Improved cytotoxic T-lymphocyte immune responses to a tumor antigen by vaccines co-expressing the SLAM-associated adaptor EAT-2.","date":"2013","source":"Cancer gene therapy","url":"https://pubmed.ncbi.nlm.nih.gov/23949283","citation_count":12,"is_preprint":false},{"pmid":"30898771","id":"PMC_30898771","title":"Cross Talk with the GAR-3 Receptor Contributes to Feeding Defects in Caenorhabditis elegans eat-2 Mutants.","date":"2019","source":"Genetics","url":"https://pubmed.ncbi.nlm.nih.gov/30898771","citation_count":9,"is_preprint":false},{"pmid":"26432891","id":"PMC_26432891","title":"Identification of the SLAM Adapter Molecule EAT-2 as a Lupus-Susceptibility Gene That Acts through Impaired Negative Regulation of Dendritic Cell Signaling.","date":"2015","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/26432891","citation_count":5,"is_preprint":false},{"pmid":"37450052","id":"PMC_37450052","title":"EAT-2 attenuates C. elegans development via metabolic remodeling in a chemically defined food environment.","date":"2023","source":"Cellular and molecular life sciences : CMLS","url":"https://pubmed.ncbi.nlm.nih.gov/37450052","citation_count":4,"is_preprint":false},{"pmid":"27586300","id":"PMC_27586300","title":"The X-ray Crystallographic Structure of Human EAT2 (SH2D1B).","date":"2016","source":"Protein and peptide letters","url":"https://pubmed.ncbi.nlm.nih.gov/27586300","citation_count":1,"is_preprint":false},{"pmid":"41142196","id":"PMC_41142196","title":"Optimizing a C. elegans whole organism screen biased for chemicals that target the nematode clade specific receptor EAT-2.","date":"2025","source":"microPublication biology","url":"https://pubmed.ncbi.nlm.nih.gov/41142196","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":11195,"output_tokens":2750,"usd":0.037417},"stage2":{"model":"claude-opus-4-6","input_tokens":6108,"output_tokens":2547,"usd":0.141322},"total_usd":0.178739,"stage1_batch_id":"msgbatch_011rkcQdVV1RaFq9XhcG6df6","stage2_batch_id":"msgbatch_01RzgrJafdF4EWHhj5mNi6dh","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2001,\n      \"finding\": \"EAT-2 (SH2D1B) is a free SH2 domain protein expressed in macrophages and B lymphocytes that binds phosphorylated SLAM family receptors (CD84, CD150/SLAM, CD229, CD244) via a pTyr motif, and acts as a natural inhibitor by interfering with recruitment of the tyrosine phosphatase SHP-2 to these receptors. Unlike SAP, EAT-2 does not bind non-phosphorylated CD150.\",\n      \"method\": \"Crystal structure of EAT-2 in complex with phosphotyrosine peptide from CD150 cytoplasmic tail; biochemical binding assays; competition assays with SHP-2\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — crystal structure plus biochemical binding and functional assays in a single study\",\n      \"pmids\": [\"11689425\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"EAT-2 associates with the SLAM-related receptor 2B4 in NK cells and inhibits NK cell natural cytotoxicity and IFN-γ secretion by a mechanism requiring tyrosine phosphorylation of its C-terminal tail. The related adaptor ERT shares this inhibitory function.\",\n      \"method\": \"EAT-2-deficient and EAT-2-overexpressing mouse models; co-immunoprecipitation; functional cytotoxicity and cytokine assays; phosphorylation studies with tyrosine mutants\",\n      \"journal\": \"Nature immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic KO/OE mice plus biochemical and functional assays, strong and replicated\",\n      \"pmids\": [\"16127454\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Upon activation, CRACC associates with EAT-2 in human NK cells; EAT-2 association induces CRACC tyrosine phosphorylation partially dependent on Src kinases, and downstream signals include PLCγ1, PLCγ2, and PI3K activation leading to NK cell cytotoxicity. EAT-2 also associates with 2B4 predominantly in resting NK cells.\",\n      \"method\": \"Co-immunoprecipitation; pharmacological Src kinase inhibition; functional cytotoxicity assays; signaling pathway analysis\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal Co-IP plus pathway dissection with inhibitors and functional readouts\",\n      \"pmids\": [\"16339536\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"EAT-2 is recruited specifically to the second tyrosine (in an ITSM motif) of NTB-A in human NK cells; this recruitment mediates NTB-A-dependent cytotoxicity but not IFN-γ production, demonstrating differential dependence on EAT-2 versus SAP for distinct NK cell effector functions.\",\n      \"method\": \"NTB-A tyrosine mutants expressed in NTB-A-negative NK cell line; SAP silencing by siRNA; functional cytotoxicity and cytokine assays\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — site-directed mutagenesis plus KD with clear functional separation of two effector outputs\",\n      \"pmids\": [\"16920955\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"CRACC positively regulates NK cell function through EAT-2 (but not SAP); in the absence of EAT-2, CRACC becomes inhibitory. In T cells, which lack EAT-2, CRACC is inhibitory. Thus EAT-2 availability determines the activating vs. inhibitory outcome of CRACC signaling.\",\n      \"method\": \"CRACC-deficient mouse; EAT-2-deficient mouse; genetic epistasis; NK cell functional assays (cytotoxicity, cytokine production)\",\n      \"journal\": \"Nature immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic epistasis with two KO mouse models and clear phenotypic rescue logic\",\n      \"pmids\": [\"19151721\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"EAT-2 mediates NK cell activation by linking SLAM family receptors to PLCγ, calcium flux, and Erk kinase signaling via one or two tyrosines in its C-terminal tail (not found in SAP). Unlike SAP, EAT-2 does not enhance NK–target conjugate formation but instead accelerates polarization and exocytosis of cytotoxic granules toward hematopoietic target cells.\",\n      \"method\": \"Genetic, biochemical (phosphorylation, co-IP), and live-imaging approaches; EAT-2 tyrosine mutants; calcium flux assays; Erk activation assays; granule polarization imaging\",\n      \"journal\": \"The Journal of experimental medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — multiple orthogonal methods including mutagenesis, biochemistry, and live imaging in a single rigorous study\",\n      \"pmids\": [\"24687958\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"CD84, upon ligation, undergoes rapid tyrosine phosphorylation and recruits both SAP and EAT-2, suggesting EAT-2 participates in signal transduction through this SLAM family receptor on B cells.\",\n      \"method\": \"Co-immunoprecipitation of SAP and EAT-2 with phosphorylated CD84; anti-CD84 antibody ligation assays on primary human B cells\",\n      \"journal\": \"European journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — single Co-IP demonstration on primary cells, no mechanistic follow-up\",\n      \"pmids\": [\"12115647\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"EAT-2 negatively regulates cytokine (IL-12) production in dendritic cells downstream of SLAM engagement by blocking activation of p38 MAPK and JNK signaling pathways following CD40 cross-linking; a NZB mouse promoter polymorphism reducing EAT-2 expression by ~70% in DCs disrupts this inhibition and promotes lupus-like autoimmunity.\",\n      \"method\": \"EAT-2 gene silencing in DCs; downstream signaling analysis (p38, JNK); T cell–DC co-culture assays; subcongenic mouse mapping\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — genetic reduction plus signaling pathway analysis, single lab\",\n      \"pmids\": [\"26432891\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"The crystal structure of human EAT-2 (SH2D1B) in unliganded form reveals conformational differences in ligand-binding loops compared with mouse EAT-2–peptide complex structure, and shows similar calculated binding energies to unphosphorylated ligands as SAP, suggesting additional factors beyond the SH2 domain contribute to the differential phosphotyrosine specificity of EAT-2 versus SAP.\",\n      \"method\": \"X-ray crystallography of human EAT-2; structural comparison with mouse EAT-2 and SAP\",\n      \"journal\": \"Protein and peptide letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 — crystal structure, but limited functional validation; single study\",\n      \"pmids\": [\"27586300\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"EAT-2 (SH2D1B) was identified as a novel gene upregulated by the EWS/FLI1 fusion oncogene; it encodes a protein containing a biochemically functional SH2 domain and its expression correlates with EWS/FLI1-mediated transformation of NIH3T3 cells.\",\n      \"method\": \"Representational difference analysis (RDA); RT-PCR; SH2 domain functional assessment; NIH3T3 transformation assay\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — original identification with biochemical SH2 activity and transformation correlation, single lab\",\n      \"pmids\": [\"9000139\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"EAT-2 overexpression enhances human NK cell anti-tumor activity, DC maturation, and monocyte phagocytosis; these effects are abolished by an R31Q mutation in the SH2 domain, indicating the interaction between EAT-2 and SLAM receptors (via its SH2 domain) is required for these immunomodulatory functions.\",\n      \"method\": \"EAT-2 overexpression in human PBMCs; R31Q SH2 mutant as negative control; NK cytotoxicity assays; DC maturation assays; phagocytosis assays\",\n      \"journal\": \"International immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 — functional assays with SH2-domain mutant control demonstrating domain requirement, single lab\",\n      \"pmids\": [\"24374770\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"SH2D1B (EAT-2) is a free SH2 domain adaptor expressed in innate immune cells (NK cells, macrophages, dendritic cells, B cells) that binds phosphorylated tyrosine motifs (ITSMs) in the cytoplasmic tails of SLAM family receptors (2B4, CRACC, NTB-A, CD84, CD150, CD229, CD244), and depending on cellular context either activates NK cells by coupling these receptors to PLCγ, calcium flux, Erk, and cytotoxic granule polarization via tyrosines in its unique C-terminal tail, or inhibits signaling (e.g., blocking SHP-2 recruitment or suppressing p38/JNK in DCs), with the net outcome determined by the availability of EAT-2 itself as a competing effector relative to the inhibitory machinery.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"SH2D1B (EAT-2) is a free SH2 domain adaptor protein that transduces signals from SLAM family receptors to control innate immune cell activation and inhibition. EAT-2 binds phosphorylated ITSM motifs in the cytoplasmic tails of SLAM family receptors (CD150, CD84, CD229, CD244/2B4, CRACC, NTB-A), competing with the phosphatase SHP-2 for receptor access and thereby modulating downstream signaling outcomes [PMID:11689425, PMID:12115647, PMID:16920955]. In NK cells, EAT-2 couples SLAM family receptors to PLCγ, calcium flux, and Erk activation through tyrosine residues in its unique C-terminal tail, promoting cytotoxic granule polarization and exocytosis toward hematopoietic targets; in the absence of EAT-2, receptors such as CRACC switch from activating to inhibitory [PMID:24687958, PMID:19151721, PMID:16339536]. In dendritic cells, EAT-2 instead functions as a negative regulator by suppressing p38 MAPK and JNK signaling downstream of SLAM engagement, restraining IL-12 production, and a promoter polymorphism reducing EAT-2 expression in NZB mice promotes lupus-like autoimmunity [PMID:26432891].\",\n  \"teleology\": [\n    {\n      \"year\": 1996,\n      \"claim\": \"Before its immune function was recognized, EAT-2 was identified as a novel SH2-domain-containing gene upregulated by the EWS/FLI1 oncogene, establishing that it encodes a functional SH2 domain protein.\",\n      \"evidence\": \"Representational difference analysis and SH2 domain functional assays in NIH3T3 cells transformed by EWS/FLI1\",\n      \"pmids\": [\"9000139\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No immune cell context examined\", \"Physiological target ligands unknown\", \"Transformation correlation not mechanistically resolved\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Structural and biochemical work revealed that EAT-2 binds phosphorylated (but not unphosphorylated) SLAM family receptor ITSMs and competes with SHP-2, establishing its mechanism as a natural inhibitor of phosphatase-mediated signaling at these receptors.\",\n      \"evidence\": \"Crystal structure of EAT-2 bound to phosphotyrosine peptide from CD150; competition assays with SHP-2\",\n      \"pmids\": [\"11689425\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of SHP-2 displacement not tested in living immune cells\", \"Whether EAT-2 also transmits positive signals was unknown\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Demonstration that CD84 ligation recruits EAT-2 in primary B cells extended the receptor repertoire for EAT-2 beyond CD150.\",\n      \"evidence\": \"Co-immunoprecipitation of EAT-2 with tyrosine-phosphorylated CD84 in human B cells\",\n      \"pmids\": [\"12115647\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No reciprocal IP or mutagenesis\", \"Downstream signaling not characterized\", \"Functional consequence in B cells not tested\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Genetic studies in mice and human NK cells showed that EAT-2 both inhibits 2B4-mediated NK cytotoxicity (via its C-terminal tyrosines) and activates CRACC-dependent NK killing (via PLCγ/PI3K), revealing that EAT-2 is not a simple inhibitor but a context-dependent signaling switch.\",\n      \"evidence\": \"EAT-2-knockout and overexpression mouse models; co-IP; cytotoxicity and IFN-γ assays; Src kinase inhibition; tyrosine-to-phenylalanine mutants\",\n      \"pmids\": [\"16127454\", \"16339536\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How EAT-2 exerts opposite effects through different SLAM receptors was unresolved\", \"Downstream signaling cascade beyond PLCγ/PI3K not fully mapped\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Mapping of EAT-2 recruitment to the second ITSM tyrosine of NTB-A showed receptor-site specificity and demonstrated that EAT-2 selectively mediates cytotoxicity but not IFN-γ production through NTB-A, establishing functional compartmentalization between EAT-2 and SAP.\",\n      \"evidence\": \"NTB-A tyrosine mutants in an NTB-A-negative NK line; SAP siRNA knockdown; cytotoxicity and cytokine assays\",\n      \"pmids\": [\"16920955\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis for ITSM selectivity not resolved\", \"Mechanism coupling EAT-2 to granule release versus cytokine pathways unknown\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Genetic epistasis between CRACC-KO and EAT-2-KO mice proved that EAT-2 availability is the molecular switch determining whether CRACC activates or inhibits NK cells, explaining why CRACC is inhibitory in T cells that lack EAT-2.\",\n      \"evidence\": \"CRACC-deficient and EAT-2-deficient mouse crosses; NK functional assays\",\n      \"pmids\": [\"19151721\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of the inhibitory effector recruited in the absence of EAT-2 not defined\", \"Whether this switch operates for all SLAM receptors was untested\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"An SH2-domain-disrupting R31Q mutation abolished EAT-2-mediated enhancement of NK cytotoxicity, DC maturation, and monocyte phagocytosis, confirming that SLAM receptor binding through the SH2 domain is essential for all tested immunomodulatory functions.\",\n      \"evidence\": \"EAT-2 and R31Q mutant overexpression in human PBMCs; NK, DC, and phagocytosis functional assays\",\n      \"pmids\": [\"24374770\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Overexpression system; endogenous levels not tested\", \"Precise receptor targets mediating DC and monocyte effects not identified\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Detailed dissection showed that C-terminal tail tyrosines of EAT-2 couple SLAM receptors to PLCγ, calcium, and Erk to drive cytotoxic granule polarization and exocytosis — a mechanism distinct from SAP, which promotes conjugate formation — thereby defining the unique effector arm of EAT-2 in NK cell killing.\",\n      \"evidence\": \"EAT-2 tyrosine mutants; calcium flux; Erk activation; live imaging of granule polarization\",\n      \"pmids\": [\"24687958\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether EAT-2 directly recruits PLCγ or acts through an intermediate kinase not resolved\", \"Contribution of individual tail tyrosines not fully dissected\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"EAT-2 was shown to function as a negative regulator in dendritic cells by suppressing p38 and JNK downstream of SLAM/CD40, restraining IL-12; a natural NZB promoter polymorphism reducing EAT-2 expression leads to enhanced DC activation and lupus-like autoimmunity.\",\n      \"evidence\": \"Gene silencing in DCs; signaling analysis; T cell–DC co-culture; subcongenic NZB mouse mapping\",\n      \"pmids\": [\"26432891\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which EAT-2 blocks p38/JNK not defined\", \"Whether the NZB polymorphism is causal or linked requires further genetic dissection\", \"Inhibitory versus activating function in DCs vs NK cells not mechanistically reconciled\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The molecular basis for how EAT-2 switches between activating (NK cell) and inhibitory (DC, T cell) outputs at different SLAM receptors remains unresolved, and no direct structural view of the EAT-2 C-terminal tail engaged with PLCγ or other effectors exists.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No structure of EAT-2 tail bound to PLCγ or downstream effectors\", \"Whether EAT-2 recruits PLCγ directly or via an adaptor is unknown\", \"Cell-type-specific co-factors that determine activating versus inhibitory outcome not identified\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 1, 2, 3, 5]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0, 5]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [1, 2, 3, 4, 5, 7, 10]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 2, 5, 7]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"CD244\", \"SLAMF7\", \"SLAMF6\", \"CD84\", \"SLAMF1\", \"SLAMF3\", \"PLCG1\", \"PTPN11\"],\n    \"other_free_text\": []\n  }\n}\n```"}