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Titolo:
Ptc1, a type 2C Ser/Thr phosphatase, inactivates the HOG pathway by dephosphorylating the mitogen-activated protein kinase Hog1
Autore:
Warmka, J; Hanneman, J; Lee, J; Amin, D; Ota, I;
Indirizzi:
Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA Univ Colorado Boulder CO USA 80309 Chem & Biochem, Boulder, CO 80309 USA
Titolo Testata:
MOLECULAR AND CELLULAR BIOLOGY
fascicolo: 1, volume: 21, anno: 2001,
pagine: 51 - 60
SICI:
0270-7306(200101)21:1<51:PAT2SP>2.0.ZU;2-3
Fonte:
ISI
Lingua:
ENG
Soggetto:
YEAST SACCHAROMYCES-CEREVISIAE; TYROSINE-SPECIFIC PHOSPHATASES; FUS3 MAP KINASE; STRESS-RESPONSE; FISSION YEAST; DIFFERENTIAL REGULATION; SIGNAL-TRANSDUCTION; PHEROMONE RESPONSE; SHUTTLE VECTORS; BUDDING YEAST;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
54
Recensione:
Indirizzi per estratti:
Indirizzo: Ota, I Univ Colorado, Dept Chem & Biochem, Campus Box 215, Boulder, CO 80309 USA Univ Colorado Campus Box 215 Boulder CO USA 80309 der, CO 80309 USA
Citazione:
J. Warmka et al., "Ptc1, a type 2C Ser/Thr phosphatase, inactivates the HOG pathway by dephosphorylating the mitogen-activated protein kinase Hog1", MOL CELL B, 21(1), 2001, pp. 51-60

Abstract

The HOG (high osmolarity glycerol) mitogen-activated protein kinase (MAPK)pathway regulates the osmotic stress response in the yeast Saccharomyces cerevisiae. Three type 2C Ser/Thr phosphatases (PTCs), Ptc1, Ptc2, and Ptc3,have been isolated as negative regulators of this pathway. Previously, multicopy expression of PTC1 and PTC3 was shown to suppress lethality of the sln1 Delta strain due to hyperactivation of the HOG pathway. In this work, we show that PTC2, also suppresses sln1 Delta lethality. Furthermore, the phosphatase activity of these PTCs was needed for suppression, as mutation ofa conserved Asp residue, likely to coordinate a metal ion, inactivated PTCs. Further analysis of Ptc1 function in vivo showed that it inactivates theMAPK, Hog1, but not the MEK, Pbs2. In the wild type, Hog1 kinase activity increased transiently, similar to 12-fold in response to osmotic stress, while overexpression of PTC1 limited activation to similar to3-fold. In contrast, overexpression of PTC1 did not inhibit phosphorylation of Hog1 Tyr in the phosphorylation lip, suggesting that Ptc1 does not act on Pbs2. Deletion of PTC1 also strongly affected Hog1, leading to high basal Hog1 activity and sustained Hog1 activity in response to osmotic stress, the latter beingconsistent with a role for Ptc1 in adaptation. In vitro, Ptc1 but not the metal binding site mutant, Ptc1D58N, inactivated Hog1 by dephosphorylating the phosphothreonine but not the phosphotyrosine residue in the phosphorylation lip. Consistent with its role as a negative regulator of Hog1, which accumulates in the nucleus upon activation, Ptc1 was found in both the nucleus and the cytoplasm. Thus, one function of Ptc1 is to inactivate Hog1.

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Documento generato il 04/06/20 alle ore 01:38:58