ArgBP2 Background Information Arg and c-Abl represent the mammalian members of the Abelson family of non-receptor protein-tyrosine kinases They interact with the Arg/Abl binding proteins (ArgBPs) via SH3 domains present in the carboxy-terminus of the ArgBPs. One member of the Arg/Abl binding protein family, ArgBP2, is expressed in epithelial and cardiac muscle cells. The subcellular localization of ArgBP2 suggests that it functions as an adapter protein in the assembly of signaling complexes in stress fibers and that it is a potential link between Abl family kinases and the Actin cytoskeleton. The human ArgBP2 gene, which maps to chromosome 4, encodes multiple transcripts that yield different isoforms of ArgBP2. Isoforms ArgBP2a and ArgBP2b differ at the 5' end but have the same carboxy-terminal sequence, containing three SH3 domains. Another member of the ArgBP family, nArgBP2, which is specifically expressed in neural tissue, has the carboxy terminal SH3 domains characteristic of Arg/Abl binding proteins, as well as a sorbin homology domain near the N-terminus and a zinc finger motif in the middle region of the protein. nArgBP2 interacts with the proline-rich region of SAPAP via its third SH3 domain. In rat brain, nArgBP2 co-localizes with SAPAP at the synapses of the
