Signal Transducing Adaptor Protein 2 (STAP2)

STAP2 encodes the substrate of breast tumor kinase, an Src-type non-receptor tyrosine kinase possesses domains and several tyrosine phosphorylation sites characteristic of adaptor proteins that mediate the interactions linking proteins involved in signal transduction pathways. One variant encodes a deduced 403-amino acid protein with a calculated molecular mass of about 45 kD.The other variant has a 138-bp insertion and encodes a deduced 449-amino acid protein with a calculated molecular mass of about 50 kD. BKS contains a PH domain, an SH2 domain, 2 putative SH3-binding sites, and several tyrosine phosphorylation sites. Western blot analysis detected proteins of 60 to 62 kD in normal breast luminal cell lines, in several breast tumor cell lines, and in most tissues tested, with the exception of skeletal muscle.