Cellular localization of Pin1 regulates the phosphorylation status of Rb

Abstract:

Retinoblastoma tumor-suppressor proteins (Rb) plays a vital role in regulation of cell proliferation and tumor development. Recent research reveals that peptidyl-prolyl isomerase (Pin1) can regulate the function of Rb. In this study, we examined the cellular localization of Pin1 in tumor tissues, and investigated the effects of Pin1 localization on Rb phosphorylation. Our data demonstrated that knockdown of Pin1 result in a decrease of Rb phosphorylation and cellular viability. Pin1 can localize to cytoplasm in cultured tumor cells and tumor tissues, while cytoplasmic Pin1 can increase the phosphorylation of Rb. This is a novel mechanism for Pin1 in regulating Rb function.