Figure 2.

Phosphorylation of FKBP52 in vivo. COS7 cells were transfected with an expression plasmid of FKBP52 (amino acids 6–458) and labeled with [³²P]orthophosphate. (A) CBB staining of proteins isolated with FK506–Affi-Gel 10 (lane 2) or with control–Affi-Gel 10 (lane 1). The positions of FKBP52 and HSP90 are indicated by arrows. Two additional associated proteins are indicated by arrowheads. (B) Autoradiography of the same gel as A. In vivo phosphorylated FKBP52 and HSP90 are indicated by arrows. (C) V8 phosphopeptide maps of in vivo- (lane 5) and in vitro- (lane 6) phosphorylated FKBP52 are shown by autoradiography. The position of original FKBP52 is indicated by an arrowhead, and phosphopeptides common to in vivo- and in vitro-phosphorylated FKBP52 are indicated by arrows.