Heat shock increases turnover of 90 kDa heat shock protein phosphate groups in HeLa cells

Legagneux, Vincent; Morange, Michel; Bensaude, Olivier

doi:10.1016/0014-5793(91)81320-8

Cited by 27 publications

(15 citation statements)

References 22 publications

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“…hsp9O is phosphorylated by casein kinase 11 (7,16,27). Legagneux et al (17) reported the increased turnover of hsp90 phosphate groups in HeLa cells submitted to heat shock, which could be explained by an increased hsp90 phosphatase activity. In vitro experiments to measure the activity of Ptcl against hsp90 and other phosphoproteins using bacterially produced and highly purified Ptcl protein are now feasible.…”

Section: Discussionmentioning

confidence: 99%

Protein phosphatase 2C, encoded by ptc1+, is important in the heat shock response of Schizosaccharomyces pombe.

et al. 1994

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Protein phosphatase 2C (PP2C), an Mg2e-dependent enzyme that dephosphorylates serine and threonine residues, defines one of the three major families of structurally unrelated eukaryotic protein phosphatases. Members Eukaryotic protein phosphatases have traditionally been classified into five broad classes on the basis of substrate amino acid specificity and cofactor requirements (2). However, gene cloning and sequencing studies have revealed that there are in fact three major evolutionary families of eukaryotic protein phosphatases. One family includes members that dephosphorylate exclusively tyrosine together with the more recently recognized dual-specificity phosphatases such as Cdc25 that dephosphorylate tyrosine and threonine in vivo (reviewed in reference 25). This is a highly divergent family, but all of its members share a conserved active site that includes a cysteine residue that is the phosphate acceptor in the dephosphorylation reaction. The second major family consists of type 1 (PP1), type 2A (PP2A), and type 2B (PP2B) serine/threonine phosphatases (2). These enzymes share -40% identity of amino acid sequence in their catalytic domains, show sensitivity to certain phosphatase inhibitors such as okadaic acid, and do not require Mg" for enzymatic activity (2). A number of new phosphatase genes whose protein products have a structural similarity to this family have been identified in a variety of species (4), and the family continues to expand.The third major protein phosphatase family is made up of type 2C enzymes (PP2C). Like the second family, these enzymes predominantly dephosphorylate serine and threonine residues, but their activity is Mg2+ dependent and resistant to okadaic acid (2). These enzymes are ubiquitous in eukaryotes; PP2C activity has been detected in a variety of species, and PP2C genes have been cloned in rats (35,36), rabbits, humans (19), and most recently in the budding yeast Saccharomyces cerevisiae (18). PP2C enzymes share -25% identity in their catalytic domains, but they have no detectable sequence similarity to the phosphatases from the other families.Genetic studies have been instrumental in unraveling the biological functions of various members of the tyrosine phosphatases and PP1/PP2A/PP2B serine/threonine phosphatases. * Corresponding author. Phone: (619) 554-6165.In addition to functions in basic processes of cellular metabolism, these phosphatases have important roles in cell cycle control, as well as regulation of cell proliferation and differentiation. In contrast, very little is known about physiological functions of PP2C, mainly because of a lack of genetic studies or a specific inhibitor of PP2C. Here we report the cloning and characterization of a PP2C gene in Schizosaccharomyces pombe. This gene, ptcl +, was isolated as a multicopy suppressor of swol-26, a temperature-sensitive mutation of a gene encoding an 82-kDa protein that is closely related to the stress protein hsp9O. ptcl + mRNA is heat inducible, and ptcl deletion mutant cells are highly sensitive to ...

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Section: Discussionmentioning

confidence: 99%

Protein phosphatase 2C, encoded by ptc1+, is important in the heat shock response of Schizosaccharomyces pombe.

et al. 1994

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“…These results agree with a previous study showing rapid dephosphorylation of Hsp90 in heat-shocked HeLa cells. 44 Loss of threonine phosphorylation may impact Hsp90 function in response to heat shock stress or to inhibitory drugs.…”

Section: Introductionmentioning

confidence: 99%

Hsp90 phosphorylation, Wee1 and the cell cycle

Mollapour

Tsutsumi²,

Neckers³

2010

Cell Cycle

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“…The Hsp90 phosphorylation level is high under physiological conditions (60). Heat shock conditions induce an increased Hsp90 phosphorylation turnover (61). All known sites reside in the N-domain of Hsp90, but so far, no specific effect can be attributed to a particular phosphorylation event.…”

Section: Post-translational Modificationsmentioning

confidence: 99%