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Fig. 1. CrkII protects p130cas from dephosphorylation. (A)
293-EBNA cells were transfected with either pRK-VSV-CrkII (2 µg) or
pRK-GFP-PTP1B (2 µg) expression plasmids, or co-transfected with
pRK-VSV-CrkII and pRK-GFP-PTP1B. Cell lysates were immunoprecipitated with
anti-p130cas (IP: p130cas), anti-paxillin (IP: paxillin)
or anti-FAK (IP: FAK) antibodies, and then immunoblotted with
anti-phosphotyrosine (Blot: pTyr), anti-p130cas (Blot:
p130cas), anti-paxillin (Blot: paxillin) or anti-FAK (Blot: FAK) antibodies.
The whole-cell lysates (WCL) were immunoblotted with anti-GFP (Blot: GFP) or
anti-VSV (Blot: VSV) antibodies. The numerical values indicate relative ratios
as a percentage of the control for each band of phosphoprotein/total protein
after scanning and analysis using NIH Image software. (B) pRK-GFP-PTP1B (2
µg) and various quantities of pcDNA-CrkII expression plasmids as indicated
were co-transfected in 293-EBNA cells. Cell lysates were immunoprecipitated
with anti-p130cas (IP: p130cas) and then immunoblotted
with anti-phosphotyrosine (Blot: pTyr), anti-p130cas
(Blot: p130cas) or anti-Crk (Blot: Crk) antibodies. The whole-cell lysates
(WCL) were immunoblotted with anti-GFP (Blot: GFP) or anti-Crk (Blot: Crk)
antibodies. The numbers indicate relative ratios as a percentage of controls
for phosphoprotein/total protein or for CrkII bound to
p130cas compared with the control.