Acts as an adapter protein of the FYN and LCP2 signaling cascades in T-cells (PubMed:9207119, PubMed:10497204). May play a role in linking T-cell signaling to remodeling of the actin cytoskeleton (By similarity). Modulates the expression of IL2 (PubMed:9207119, PubMed:10497204). Involved in platelet activation (PubMed:17003372). Prevents the degradation of SKAP1 and SKAP2 (By similarity). May be involved in high affinity immunoglobulin epsilon receptor signaling in mast cells (PubMed:12681493). Part of a complex consisting of SKAP2, FYB1 and PTPNS1 (PubMed:10469599). Part of a complex consisting of SKAP2, FYB1 and LILRB3 (PubMed:10469599). Part of a complex consisting of SKAP1, FYB1 and CLNK (PubMed:12681493). Interacts with CLNK (via its SH2 domain); this interaction allows SKAP1 and FYB1 to recruit FYN to the complex, thus promoting the phosphorylation of CLNK by FYN (PubMed:12681493, PubMed:10497204, PubMed:9207119). Interacts with FYN (PubMed:9207119, PubMed:10497204). Interacts with LCP2 (PubMed:9207119, PubMed:10497204). Interacts with SKAP1 (PubMed:12681493). Interacts with SKAP2 (PubMed:10469599, PubMed:11207596, PubMed:17003372). Interacts with FASLG (By similarity). Interacts with EVL (By similarity). Interacts with TMEM47 (PubMed:21881001). Interacts with LCK (By similarity). Colocalizes with TMEM47 at cell-cell contacts in podocytes. Expressed in hematopoietic tissues such as myeloid and T-cells, spleen and thymus. Not expressed in B-cells, nor in non-lymphoid tissues. FYB-130 is preferentially expressed in mature T-cells compared to FYB-120, whereas thymocytes showed a greater relative amount of FYB-120. Expressed in podocytes. T-cell receptor ligation leads to increased tyrosine phosphorylation. Slight defects in platelet function.