title: Site-specific and temporally-regulated retinoblastoma protein dephosphorylation by protein phosphatase type 1.
abstract: pRb is dephosphorylated at mitotic exit by the type 1 serine/threonine protein phosphatases (PP1). Here we demonstrate for the first time that mitotic pRb dephosphorylation is a sequential, temporally-regulated event. We also provide evidence that the three mammalian isoforms of PP1, alpha, gamma-1, and delta, differ in their respective preferences for site-specific pRb dephosphorylation and that the mitotic and G(1) PP1-isoform counterparts exhibit differential activities towards mitotic pRb. Finally, the physiological relevance of the striking contrast between the patterns of Thr821 and Thr826 dephosphorylation, sites known to be important for disrupting binding of LXCXE-containing proteins to pRb, is addressed.
authors: Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York, NY 14642, USA.
authors: E
authors: E
authors: Rubin
authors: S
authors: S
authors: Mittnacht
authors: E
authors: E
authors: Villa-Moruzzi
authors: J W
authors: JW
authors: Ludlow
mesh_terms: D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D002522:Chlorocebus aethiops; D016193:G1 Phase; D007527:Isoenzymes / Q000378:metabolism; D008938:Mitosis / Q000502:physiology; D010749:Phosphoprotein Phosphatases / Q000378:metabolism*; D010766:Phosphorylation; D016160:Retinoblastoma Protein / Q000378:metabolism*; D013912:Threonine / Q000378:metabolism
chemical_list: D007527:Isoenzymes; D016160:Retinoblastoma Protein; D013912:Threonine; D010749:Phosphoprotein Phosphatases