Dok1 (Ser-450), Phosphospecific Antibody

Doks are a family of adaptor proteins that include six Dok proteins (Dok1 to Dok6), which have an N-terminal pleckstrin homology domain, a central phosphotyrosine binding domain, and a C-terminal region containing multiple tyrosine residues. When phosphorylated, these tyrosines can serve as docking sites for SH2 domain-containing proteins. Dok1 (p62dok) has been shown to bind Ras-GAP, Nck, and Csk. Several tyrosine phosphorylation sites have been identified for Dok1. One site, Tyr-362 (Tyr-361 mouse), is phosphorylated by c-Abl, is required for Nck binding, and may be critical for filopodia formation during fibroblast spreading on fibronectin. Alternatively, Dok1 activity is also regulated by serine phosphorylation. IκB Kinase β phosphorylates several serine sites including Ser-450 in vitro, and TNFα, IL-1, and radiation treatment lead to phosphorylation of Ser-443, Ser-446, and Ser-450 in vivo. Phosphorylation of these serine sites may be required for Dok-mediated inhibition of MAPK signaling and stimulation of cell motility.

This antibody was cross-adsorbed to an unphosphorylated Dok1 (Ser-450) peptide before affinity purification using phospho-Dok1 (Ser-450) peptide. The purified antibody detects a band at 62 kDa* corresponding to Dok1 in western blots of human Jurkat cells, but does not detect this band after lambda phosphatase treatment.