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Fig. 4. Deletion effect of Cas domain structure on Cas-induced Rap1 activation. (A)
Schematic representation of Cas variants used for the evaluation of Rap1
activation competence. (B) Overexpression effect of Cas and its deletion
mutants on Rap1 activity was examined as in
Fig. 1. Cas overexpression
increases the amount of GTP-bound Rap1 compared with control pCAX
transfectant. Cas
SD failed to activate Rap1, whereas Cas
SCB
substantially retained the activity. (C) Tyrosine phosphorylation and Crk
interaction of Cas mutants. 293T cells were transfected with a Cas derivative
expression plasmid together with Crk. After immunoprecipitation with anti-HA
antibody, the tyrosine phosphorylation levels of Cas proteins and
co-immunoprecipitated Crk in the immunoprecipitates were analyzed.