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). 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). May be involved in the BCAR1/CAS-mediated JNK activation pathway. Component of a complex comprised of SH2D3C, BCAR1/CAS, and CRK (PubMed:12432078). Within the complex, interacts with CRK and (via C-terminus) with BCAR1/CAS (via C-terminus) (PubMed:12432078, PubMed:17174122, PubMed:22081014). Interacts with NEDD9/HEF1 (By similarity). Interacts with EPHB2 (By similarity). Interacts with NEDD9/HEF1 (By similarity). Interacts with BCAR1/CAS (By similarity). Interacts with PTK2B (By similarity). Interacts (via C-terminus) with BCAR1/CAS (via C-terminus) (By similarity). Interacts with IGF1 (PubMed:20881139). Associated with the membrane when EGF-stimulated (By similarity). Expressed at the cortical actin ring in B cells (By similarity). Ubiquitously expressed. The C-terminal Cdc25-homology/Ras-GEF domain adopts a closed conformation rendering it incapable of carrying out canonical exchange factor function, this closed conformation is required for interaction with BCAR1. Phosphorylated by MAPK/ERK upon T-cell receptor stimulation in T-cells.