Nuclear localization of protein phosphatase 5 is dependent on the carboxy‐terminal region

Borthwick, Emma B.; Zeke, Tamás; Prescott, Alan R.; Cohen, Patricia T.W.

doi:10.1016/s0014-5793(01)02177-9

Cited by 55 publications

(63 citation statements)

References 28 publications

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“…The import of PP5 into the nucleus apparently depends on its terminal 80 aa residues (29). One of the transduced HeLa subclones, PP5.C7, expressed a protein that encodes the first 389 residues of PP5 fused to GFP, thus lacking the sequence required for nuclear import.…”

Section: Dominant Negative and Decreased Expression Of Pp5 Increase Pmentioning

confidence: 99%

DNA–PKcs function regulated specifically by protein phosphatase 5

Wechsler

Chen

Harper

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

131

110

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Unrepaired DNA double-strand breaks can lead to apoptosis or tumorigenesis. In mammals double-strand breaks are repaired mainly by nonhomologous end-joining mediated by the DNA-PK complex. The core protein of this complex, DNA-PKcs, is a DNAdependent serine͞threonine kinase that phosphorylates protein targets as well as itself. Although the (auto)phosphorylation activity has been shown to be essential for repair of both random double-strand breaks and induced breaks at the immunoglobulin locus, the corresponding phosphatase has been elusive. In fact, to date, none of the putative phosphatases in DNA double-strand break repair has been identified. Here we show that protein phosphatase 5 interacts with DNA-PKcs and dephosphorylates with surprising specificity at least two functional sites. Cells with either hypo-or hyperphosphorylation of DNA-PKcs at these sites show increased radiation sensitivity.

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Section: Dominant Negative and Decreased Expression Of Pp5 Increase Pmentioning

confidence: 99%

DNA–PKcs function regulated specifically by protein phosphatase 5

Wechsler

Chen

Harper

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

131

110

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“…Fostriecin, which inhibits PP2A (half-maximal inhibitory concentration (IC 50 ) 5 nM) 34 at levels 10 000-fold less than required for PP5 inhibition (IC 50 70 mM), 35 also had no influence on ssAAV-mediated transduction at 100 nM concentration. However, 100 nM cantharidin, which is an inhibitor of PP2A (IC 50 40 nM) and PP5 (IC 50 50 nM), and okadaic acid, which is an inhibitor of PP1 (IC 50 10-15 nM), PP2A (IC 50 100 pM) and PP5 (IC 50 7 nM), 36 decreased the transduction efficiency of ssAAV vectors by B40%. These results suggest that inhibitors of PP5, but not inhibitors of PP1, PP2A or PP2B, affect the ssAAV transduction efficiency presumably by inhibiting Ser/ Thr dephosphorylation of FKBP52, which in turn, inhibits the viral second-strand DNA synthesis.…”

mentioning

confidence: 99%

Adeno-associated virus 2-mediated gene transfer: role of a cellular serine/threonine protein phosphatase in augmenting transduction efficiency

Zhao

Zhong

et al. 2006

Gene Ther

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We have documented that a cellular chaperone protein, FKBP52, when phosphorylated at tyrosine and/or serine/ threonine (Ser/Thr) residues, interacts with the D-sequence in the inverted terminal repeats of the adeno-associated virus 2 (AAV) genome, inhibits the viral second-strand DNA synthesis, and leads to inefficient transgene expression from recombinant AAV vectors in certain cell types. We have also demonstrated that FKBP52 is dephosphorylated at tyrosine residues by T-cell protein tyrosine phosphatase (TC-PTP), and that deliberate overexpression of TC-PTP leads to more efficient viral second-strand DNA synthesis, and increased transgene expression. However, the identity of the putative Ser/Thr protein phosphatase that dephosphorylates FKBP52 at Ser/Thr residues has remained elusive. Using known inhibitors of Ser/Thr phosphatases, we have now identified protein phosphatase 5 (PP5) to be a candidate enzyme.Deliberate overexpression of PP5 in 293 cells, which does not influence cellular growth, leads to B5-fold increase in the transduction efficiency of conventional single-stranded AAV vectors, but no significant enhancement in the transduction efficiency of self-complementary AAV vectors, suggesting that PP5 plays a role in AAV second-strand DNA synthesis. Electrophoretic mobility-shift assays show that in cells overexpressing PP5, the extent of the complex formation between FKBP52 and the AAV D-sequence is significantly reduced. These studies suggest that PP5-mediated dephosphorylation of FKBP52 at Ser/Thr residues augments viral second-strand DNA synthesis and enhances AAV transduction efficiency, which has implications in the optimal use of these vectors in human gene therapy.

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“…Recently, the ability of PP5 to translocate to the nucleus during apoptosis has been reported (10). PP5 has an atypical nuclear localization signal in its C-terminal extension (11). Cytoplasmic PP5 has been found to interact with the intermediate chain of cytoplasmic dynein and to colocalize with both cytoplasmic dynein and microtubules (12).…”

mentioning

confidence: 99%

Regulation of Apoptosis Signal-regulating Kinase 1 (ASK1) by PolyamineLevels via Protein Phosphatase5

Kutuzov

Андреева

Voyno-Yasenetskaya

2005

Journal of Biological Chemistry

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Recent evidence has implicated the protein phosphatase PP5 in a variety of signaling pathways. Whereas several proteins have been identified that interact with PP5 and regulate its activity, a possibility of its regulation by second messengers remains speculative. Activation of PP5 in vitro by polyunsaturated fatty acids (e.g. arachidonic acid) and fatty acyl-CoA esters (e.g. arachidonoyl-CoA) has been reported. We report here that PP5 is strongly inhibited by micromolar concentrations of a natural polyamine spermine. This inhibition was observed both in assays with a low molecular weight substrate p-nitrophenyl phosphate as well as phosphocasein and apoptosis signal-regulating kinase 1 (ASK1), thought to be a physiological substrate of PP5. Furthermore, a decrease in polyamine levels in COS-7 cells induced by ␣-difluoromethylornithine (DFMO), an inhibitor of ornithine decarboxylase, led to accelerated dephosphorylation of oxidative stress-activated ASK1. This effect was suppressed by okadaic acid and by siRNA-mediated PP5 depletion, indicating that the effect of polyamine levels on ASK1 dephosphorylation was mediated by PP5. In line with the decreased ASK1 activation, polyamine depletion in COS-7 cells abrogated oxidative stress-induced activation of caspase-3, which executes ASK1-induced apoptosis, as well as caspase-3 activation induced by ASK1 overexpression, but had no effect on basal caspase-3 activity. These results implicate polyamines, emerging intracellular signaling molecules, as potential physiological regulators of PP5. Our findings also suggest a novel mechanism of the antiapoptotic action of a decrease in polyamine levels via de-inhibition of PP5 and accelerated dephosphorylation and deactivation of ASK1.

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Nuclear localization of protein phosphatase 5 is dependent on the carboxy‐terminal region

Cited by 55 publications

References 28 publications

DNA–PKcs function regulated specifically by protein phosphatase 5

DNA–PKcs function regulated specifically by protein phosphatase 5

Adeno-associated virus 2-mediated gene transfer: role of a cellular serine/threonine protein phosphatase in augmenting transduction efficiency

Regulation of Apoptosis Signal-regulating Kinase 1 (ASK1) by PolyamineLevels via Protein Phosphatase5

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