The evolutionarily conserved arrangement of domains in SRC family kinases is important for substrate recognition.
The SH3-SH2-kinase domain arrangement in nonreceptor tyrosine kinases has been conserved throughout evolution. For Src family kinases, the relative positions of the domains are important for enzyme regulation; they permit the assembly of Src kinases into autoinhibited conformations. The SH3 and SH2 domains of Src family kinases have an additional role in determining the substrate specificity of the kinase. We addressed the question of whether the domain arrangement of Src family kinases has a role in substrate specificity by producing mutants with alternative arrangements. Our results suggest that changes in the positions of domains can lead to specific changes in the phosphorylation of Sam68 and Cas by Src. Phosphorylation of Cas by several mutants triggers downstream signaling leading to cell migration. The placement of the SH2 domain with respect to the catalytic domain of Src appears to be especially important for proper substrate recognition, while the placement of the SH3 domain is more flexible. The results suggest that the involvement of the SH3 and SH2 domains in substrate recognition is one reason for the strict conservation of the SH3-SH2-kinase architecture.
Yadav
Shalini S
SS
Department of Physiology and Biophysics, School of Medicine, Stony Brook University, Stony Brook, New York 11794-8661, USA.
Miller
W Todd
WT
D000595:Amino Acid Sequence; D005075:Biological Evolution; D015153:Blotting, Western; D002460:Cell Line; D017124:Conserved Sequence; D047468:Immunoprecipitation; D009154:Mutation; D013379:Substrate Specificity; D019061:src-Family Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D019061:src-Family Kinases