Fig. 4. Tyrosine phosphorylation of actin. Ax-2 and pVEII-AS5'-1 cells were shaken in KK₂ buffer in the presence or absence of 0.4 M sorbital for the indicated times and lysed in 1% SDS buffer containing 100 mM Na₂VO₄. The cell lysates were separated by SDS-PAGE, blotted onto nitrocellulose and probed with a phosphotyrosine-specific monoclonal antibody.