Acts as an adapter protein that mediates cell signaling pathways involved in cellular functions such as cell adhesion and migration, tissue organization, and the regulation of the immune response (PubMed:12432078, PubMed:20881139). Plays a role in integrin- mediated cell adhesion through BCAR1-CRK-RAPGEF1 signaling and activation of the small GTPase RAP1 (PubMed:12432078). Promotes cell migration and invasion through the extracellular matrix (PubMed:20881139). Required for marginal zone B-cell development and thymus-independent type 2 immune responses (By similarity). Mediates migration and adhesion of B cells in the splenic marginal zone via promoting hyperphosphorylation of NEDD9/CASL (By similarity). Plays a role in CXCL13-induced chemotaxis of B-cells (By similarity). Plays a role in the migration of olfactory sensory neurons (OSNs) into the forebrain and the innervation of the olfactory bulb by the OSN axons during development (By similarity). Required for the efficient tyrosine phosphorylation of BCAR1 in OSN axons (By similarity). {ECO:0000250|UniProtKB:Q9QZS8, ECO:0000269|PubMed:12432078, ECO:0000269|PubMed:20881139}. [Isoform 1]: Important regulator of chemokine-induced, integrin-mediated T lymphocyte adhesion and migration, acting upstream of RAP1 (By similarity). Required for tissue-specific adhesion of T lymphocytes to peripheral tissues (By similarity). Required for basal and CXCL2 stimulated serine-threonine phosphorylation of NEDD9 (By similarity). May be involved in the regulation of T-cell receptor- mediated IL2 production through the activation of the JNK pathway in T- cells (By similarity). . [Isoform 2]: May be involved in the BCAR1/CAS-mediated JNK activation pathway. . This is the function of Ensembl gene identifier ENSG00000095370 (SH2D3C, SH2 domain containing 3C).