Characterization of the Active Site and a Unique Uncompetitive Inhibitor of the PPM1-Type Protein Phosphatase PPM1D

Chuman, Yoshiro; Yagi, Hiroaki; Fukuda, Teruyo; Nomura, Takao; Matsukizono, Miho; Shimohigashi, Yasuyuki; Sakaguchi, Kazuyasu

doi:10.2174/092986608785849236

Cited by 24 publications

(28 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We annotated the alignment by including designation of the motifs characteristic of the PP2C superfamily (4) and metal-coordinating residues. We also aligned the sequence of Wip1, for which no structural information is available (38, 42). Following the metal ion numbering given previously (21), we refer to the metal ion that is coordinated by PP2Cα Asp60, Asp239 and Asp282 as M1, and the metal ion that is coordinated by Asp38, Asp60, and Gly61 as M2.…”

Section: Resultsmentioning

confidence: 99%

Binding of a Third Metal Ion by the Human Phosphatases PP2Cα and Wip1 Is Required for Phosphatase Activity

et al. 2013

View full text Add to dashboard Cite

The PPM phosphatases require millimolar concentrations of Mg2+ or Mn2+ to activate phosphatase activity in vitro. The human phosphatases PP2Cα (PPM1A) and Wip1 (PPM1D) differ in their physiological function, substrate specificity, and apparent metal affinity. A crystallographic structure of PP2Cα shows only two metal ions in the active site. However, recent structural studies of several bacterial PP2C phosphatases have indicated three metal ions in the active site. Two residues that coordinate the third metal ion are highly conserved, suggesting that human PP2C phosphatases may also bind a third ion. Here, isothermal titration calorimetry analysis of Mg2+ binding to PP2Cα distinguished binding of two ions to high affinity sites from the binding of a third ion with a millimolar affinity, similar to the apparent metal affinity required for catalytic activity. Mutational analysis indicated that Asp239 and either Asp146 or Asp243 was required for low-affinity binding of Mg2+, but that both Asp146 and Asp239 were required for catalysis. Phosphatase activity assays in the presence of MgCl2, MnCl2, or mixtures of the two, demonstrate high phosphatase activity toward a phosphopeptide substrate when Mg2+ was bound to the low-affinity site, whether Mg2+ or Mn2+ ions were bound to the high affinity sites. Mutation of the corresponding putative third metal ion-coordinating residues of Wip1 affected catalytic activity similarly both in vitro and in human cells. These results suggest that phosphatase activity toward phosphopeptide substrates by PP2Cα and Wip1 requires the binding of a Mg2+ ion to the low-affinity site.

show abstract

Section: Resultsmentioning

confidence: 99%

Binding of a Third Metal Ion by the Human Phosphatases PP2Cα and Wip1 Is Required for Phosphatase Activity

et al. 2013

View full text Add to dashboard Cite

show abstract

“…Since WIP1 structure has still not been determined, molecular models based on its homology with PPM1A (sharing ∼35% sequence identity) represent the only resource of information about WIP1 structure [80, 81]. Like the other PP2Cs, WIP1 acts as monomer consisting of the N-terminal catalytic domain (amino acids 1-375) and a presumably unstructured C-terminal tail [82].…”

Section: Predicted Structure Of Wip1 Phosphatasementioning

confidence: 99%

“…A unique flap sub-domain resides in the catalytic domain close to the active site and can influence binding of different substrates by allosteric modulation [80]. Part of the flap domain is a basic amino acid-rich region (called B-loop; amino acids 235–268) that was proposed to bind to negatively charged phosphate on substrates [81]. In vitro studies established that WIP1 can specifically recognize two distinct substrate motifs, namely pSQ/pTQ (present in ATM, p53, MDM2, γH2AX, Chk1, Chk2) and pTxpY (present in the active form of p38 MAPK) [8].…”

Section: Predicted Structure Of Wip1 Phosphatasementioning

confidence: 99%

WIP1 phosphatase as pharmacological target in cancer therapy

2017

View full text Add to dashboard Cite

DNA damage response (DDR) pathway protects cells from genome instability and prevents cancer development. Tumor suppressor p53 is a key molecule that interconnects DDR, cell cycle checkpoints, and cell fate decisions in the presence of genotoxic stress. Inactivating mutations in TP53 and other genes implicated in DDR potentiate cancer development and also influence the sensitivity of cancer cells to treatment. Protein phosphatase 2C delta (referred to as WIP1) is a negative regulator of DDR and has been proposed as potential pharmaceutical target. Until recently, exploitation of WIP1 inhibition for suppression of cancer cell growth was compromised by the lack of selective small-molecule inhibitors effective at cellular and organismal levels. Here, we review recent advances in development of WIP1 inhibitors and discuss their potential use in cancer treatment.

show abstract

“…One of the transcriptional targets of p53 is the type 2C S/T phosphatase protein phosphatase magnesiumdependent 1 (PPM1D), also known as wild-type p53-induced phosphatase 1 (Wip1), which preferentially targets phospho-S and phospho-T residues in the SQ/TQ motifs and phospho-T residues in the TXY motifs (Lu et al, 2004;Yamaguchi et al, 2007;Lu et al, 2008;Chuman et al, 2008). PPM1D expression is known to be induced by p53 in response to genotoxic stress (Choi et al, 2000) and it dephosphorylates both phospho-p53 at Ser 15 (Lu et al, 2007) and phospho-Chk1 at Ser 345 (Lu et al, 2005), significantly reducing Chk1 kinase activity (Capasso et al, 2002).…”

mentioning

confidence: 99%

The oncogenic phosphatase PPM1D confers cisplatin resistance in ovarian carcinoma cells by attenuating checkpoint kinase 1 and p53 activation

2011

View full text Add to dashboard Cite

Cisplatin (CDDP: cis-diamminedichloroplatinum) resistance is a major hurdle in the treatment of human ovarian cancer (OVCA). A better understanding of the mechanisms of CDDP resistance can greatly improve therapeutic outcome for patients. A determinant of CDDP sensitivity in OVCA, p53, is activated by checkpoint kinase 1 (Chk1) in response to DNA damage. Although the oncogenic phosphatase protein phosphatase magnesium-dependent 1 (PPM1D) can deactivate both p53 and Chk1 through sitespecific dephosphorylation, whether PPM1D has a role in CDDP resistance is unknown. Here, using pair-matched wild-type p53 CDDP-sensitive (OV2008) and -resistant (C13*) cells, and p53-compromised CDDP-resistant cells (A2780cp, OCC-1, OVCAR-3 and SKOV3), we have demonstrated (i) the existence of site-specific differences in phospho-Ser-Chk1 content between sensitive and resistant cells in response to CDDP; (ii) PPM1D, but not phosphoinositide-3-kinase-related kinase (ataxia telangiectasia and Rad3 related protein (ATR)), is important in the regulation of CDDP-induced Chk1 activation and OVCA cell chemosensitivity; (iii) PPM1D downregulation sensitizes resistant cells to CDDP primarily by activating Chk1 and p53. Our findings establish for the first time that PPM1D confers CDDP resistance in OVCA cells through attenuating CDDP-induced, Chk1-mediated, p53-dependent apoptosis. These findings extend the current knowledge on the molecular and cellular basis of cisplatin resistance and offer the rationale for PPMID as a potential target for treatment of chemoresistant OVCA.

show abstract

Characterization of the Active Site and a Unique Uncompetitive Inhibitor of the PPM1-Type Protein Phosphatase PPM1D

Cited by 24 publications

References 36 publications

Binding of a Third Metal Ion by the Human Phosphatases PP2Cα and Wip1 Is Required for Phosphatase Activity

Binding of a Third Metal Ion by the Human Phosphatases PP2Cα and Wip1 Is Required for Phosphatase Activity

WIP1 phosphatase as pharmacological target in cancer therapy

The oncogenic phosphatase PPM1D confers cisplatin resistance in ovarian carcinoma cells by attenuating checkpoint kinase 1 and p53 activation

Contact Info

Product

Resources

About