SLP-76 is a human Src homology domain-containing leukocyte protein. This cytoplasmic adaptor phosphoprotein contains both SH2 and SAM domains and is involved in B and T cell receptor signaling. The amino terminus of this protein contains three 17 amino acid repeats with conserved tyrosine and acidic residues (DYE(S/P)P) as well as a proline rich region and is known to associate with many proteins involved in T and B cell signaling including Grb2, LAT, Vav1, SLAP-130, SHP-1, and phospholipase C gamma 2. SLP-76 can be phosphorylated on multiple tyrosine residues by the upstream kinases ZAP-70 and Lck. SLP-76 phosphorylation plays an important role in T cell-mediated IL-2 production by allowing phosphorylated Vav to bind; this complex (SLP-76/Vav) stimulates NF-AT and IL-2 gene activation after TCR engagement. Overexpression of SLP-76 has been shown to result in enhanced IL-2 transcription after TCR signaling. The H76 monoclonal antibody recognizes human SLP-76 and has been shown to be useful for Western blotting.