Figure 5. pI shift of Hsp90 in 2D-gel electrophoresis and 15d-PGJ2 induced phosphorylation of several chaperones.

A, Representative immunoblots of three independent experiments of Hsp90 cytosolic (A375) and B, total cell lysate (A375 and 1205Lu). C, 2D-gel electrophoresis of 15d-PGJ2 or DMSO treated A375 melanoma cells with additional three dimensional versions. D, For immunoprecipitation, an anti-phosphoserine antibody was applied to cytoplasmic protein fractions. In case of the four listed chaperones, an apparent down-regulation observed by shotgun proteomics was actually accompanied by phosphorylation as evidenced by increased binding to anti-phosphoserine antibody. Protein abundances were estimated from the number of distinct peptides identified per protein.