Regulation of c-Src activity by the expression of wild-type v-Src and its kinase-dead double Y416F-K295N mutant.
Active, wild-type v-Src and its kinase-dead double Y416F-K295N mutant were expressed in hamster fibroblasts. Expression of the active v-Src induced activation of endogenous c-Src and increased general protein-tyrosine phosphorylation in the infected cells. Expression of the kinase-dead mutant induced hypophosphorylation of Tyr416 of the endogenous c-Src. The inactivation of c-Src was reversible, as confirmed by in vitro kinase activity of c-Src immunoprecipitated from the kinase-dead v-Src-expressing cells. Both activation and inactivation of c-Src may be explained by direct interaction of the v-Src and c-Src that may either facilitate transphosphorylation of the regulatory Tyr416 in the activation loop, or prevent it by formation of transient dead-end complexes of the Y416F-K295N mutant with c-Src. The interaction was also indicated by co-localization of v- and c-Src proteins in immunofluorescent images of the infected cells. These results suggest that dimerization of Src plays an important role in the regulation of Src tyrosine kinase activity.
Vojtechová
Martina
M
Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Flemingovo n. 2, 166 37 Praha 6, Czech Republic. vojtech@img.cas.cz
Senigl
Filip
F
Sloncová
Eva
E
Tuhácková
Zdena
Z
D000081247:CSK Tyrosine-Protein Kinase; D002460:Cell Line; D004789:Enzyme Activation; D005347:Fibroblasts / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D006801:Humans; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D015688:Oncogene Protein pp60(v-src) / Q000235:genetics* / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D013329:Structure-Activity Relationship; D019061:src-Family Kinases
D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D015688:Oncogene Protein pp60(v-src); D019061:src-Family Kinases; C000631346:CSK protein, human