Fig. 4. Association of endogenous poly(A) polymerase (PAP) with 14-3-3 proteins in vivo. (A) Immunoprecipitations were performed on lysates of untransfected NIH 3T3 cells using anti-14-3-3ε. Proteins were detected by western blot analysis using anti-PAP antibody. (B) The same lysates were immunoprecipitated with anti-PAP and immunoblotted with the indicated anti-14-3-3-isoform-specific antibodies. T, total lysate (2% input); C, preimmune used as a control antibody; His-PAP, the purified His-PAP used as a size marker; IP, immunoprecipitates with anti-14-3-3 proteins or anti-PAP.