An adapter protein which plays a role in the regulation of immunoreceptor signaling, including PLC-gamma-mediated B-cell antigen receptor (BCR) signaling and FC-epsilon R1-mediated mast cell degranulation (By similarity). Together with FGR, it acts as a negative regulator of natural killer cell-activating receptors and inhibits interferon-gamma production (By similarity). Acts as a positive regulator of both T-cell receptor and natural killer T (NKT) cell receptor signaling in CD4-positive NKT cells (By similarity). Together with MAP4K1, it enhances CD3-triggered activation of T-cells and subsequent IL2 production (By similarity). May be involved in tumor necrosis factor induced cell death by promoting reactive oxidative species generation, and MLKL oligomerization, ultimately leading to necrosis (By similarity). Involved in phosphorylation of LAT (By similarity). May be involved in high affinity immunoglobulin epsilon receptor signaling in mast cells (By similarity). When phosphorylated, interacts with PLCG1, PLCG2, GRB2, VAV and LAT (By similarity). Interacts with LBR and AGO2 (PubMed:26009488). Interacts with FGR (By similarity). Part of a complex consisting of CLNK, SKAP1 and FYB1 (By similarity). Interacts (via SH2 domain) with FYB1; this interaction allows SKAP1 and FYB1 to promote tyrosine phosphorylation of CLNK by LYN (By similarity). Interacts (via SH2 domain) with MAP4K1 (By similarity). The N-terminal proline-rich region interacts with the SH3 domain of PLCG1. The SH2 domain is important for restoration of BCR-induced calcium response and JNK2 activation in BLNK-deficient DT40 cells expressing LAT. Tyrosine-phosphorylated upon BCR cross-linking. Tyrosine phosphorylation at both Tyr-69 and Tyr-96 are required for BCR-induced calcium response and are essential to restore PLCG2-mediated signaling in BLNK-deficient DT40 cells, but this phosphorylation is dispensable in cells expressing LAT. Interacts with the SH2 domain of PLCG1 via phosphorylated Tyr-96 (By similarity). Tyrosine phosphorylation is increased when complexed with SKAP1 and FYB1 (By similarity).