Figure 1. HSP27 associates with nonphosphorylated p27^Kip1. A) Immunoprecipitation (IP) performed with an anti-HSP27 antibody (Ab) was followed by immunodetection of p27^Kip1, Thr¹⁸⁷-phosphorylated p27^Kip1, and Ser-10-phosphorylated p27^Kip1 in control (Co) and HSP27-transfected U937 cells nontreated or treated with GTN (500 µM, 24 h). An anti-HSP70 Ab and a nonrelevant immunoglobulin G1 (IgG) were used as controls. B) Cellular concentration of p27^Kip1, Thr¹⁸⁷-phosphorylated p27^Kip1, Ser-10-phosphorylated p27^Kip1, p21, and HSC70 were detected by Western blot in control (Co) and HSP27-transfected U937 cells nontreated or treated with GTN (500 µM, 24 h). C) Subcellular localization of HSP27 and p27^Kip1 in U937 HSP27-transfected cells left untreated (NT) or treated with GTN (500 µM, 24 h) or serum depleted for 48 h (SD).