title: Pin1-dependent prolyl isomerization regulates dephosphorylation of Cdc25C and tau proteins.
abstract: The reversible protein phosphorylation on serine or threonine residues that precede proline (pSer/Thr-Pro) is a key signaling mechanism for the control of various cellular processes, including cell division. The pSer/Thr-Pro moiety in peptides exists in the two completely distinct cis and trans conformations whose conversion is catalyzed specifically by the essential prolyl isomerase Pin1. Previous results suggest that Pin1 might regulate the conformation and dephosphorylation of its substrates. However, it is not known whether phosphorylation-dependent prolyl isomerization occurs in a native protein and/or affects dephosphorylation of pSer/Thr-Pro motifs. Here we show that the major Pro-directed phosphatase PP2A is conformation-specific and effectively dephosphorylates only the trans pSer/Thr-Pro isomer. Furthermore, Pin1 catalyzes prolyl isomerization of specific pSer/Thr-Pro motifs both in Cdc25C and tau to facilitate their dephosphorylation by PP2A. Moreover, Pin1 and PP2A show reciprocal genetic interactions, and prolyl isomerase activity of Pin1 is essential for cell division in vivo. Thus, phosphorylation-specific prolyl isomerization catalyzed by Pin1 is a novel mechanism essential for regulating dephosphorylation of certain pSer/Thr-Pro motifs.
authors.affiliation: Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA.
authors.forename: X Z
authors.initials: XZ
authors.lastname: Zhou
authors.forename: O
authors.initials: O
authors.lastname: Kops
authors.forename: A
authors.initials: A
authors.lastname: Werner
authors.forename: P J
authors.initials: PJ
authors.lastname: Lu
authors.forename: M
authors.initials: M
authors.lastname: Shen
authors.forename: G
authors.initials: G
authors.lastname: Stoller
authors.forename: G
authors.initials: G
authors.lastname: Küllertz
authors.forename: M
authors.initials: M
authors.lastname: Stark
authors.forename: G
authors.initials: G
authors.lastname: Fischer
authors.forename: K P
authors.initials: KP
authors.lastname: Lu
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology; D018797:Cell Cycle Proteins / Q000378:metabolism*; D007536:Isomerism; D007700:Kinetics; D016296:Mutagenesis; D016297:Mutagenesis, Site-Directed; D000072340:NIMA-Interacting Peptidylprolyl Isomerase; D019696:Peptidylprolyl Isomerase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D010769:Phosphothreonine / Q000378:metabolism; D017354:Point Mutation; D015398:Signal Transduction; D013379:Substrate Specificity; D013552:Swine; D020687:cdc25 Phosphatases / Q000378:metabolism*; D016875:tau Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; D000072340:NIMA-Interacting Peptidylprolyl Isomerase; D016875:tau Proteins; D010769:Phosphothreonine; D010768:Phosphoserine; D010749:Phosphoprotein Phosphatases; D020687:cdc25 Phosphatases; D019696:Peptidylprolyl Isomerase