Enhanced UV sensitivity of yeast cells induced by overexpression of Mg2+-dependent protein phosphatase α (type 2C α)

Kobayashi, Toshihide; Yasui, Akira; Ohnishi, Motoko; Kato, Shunsuke; Sasahara, Yoji; Kusuda, Kazuyuki; Chida, Naoki; Yanagawa, Yuchio; Hiraga, Akira; Tamura, Shinji

doi:10.1016/0921-8777(95)00036-4

Cited by 8 publications

(8 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The PP2C family consist of multiple isoforms including PP2C␣ (34), PP2C␤ (␤-1, -2, -3, -4, and -5) (35), PP2C␥ (36), Wip1 (37), and FIN13 (38) in mammals. Although little is known of their physiological role, they appear to function in Ca 2ϩ -dependent signal transduction (39), DNA repair systems (40), mitogenactivated protein kinase systems (41), and the dephosphorylation of cofilin (42).…”

Section: Discussionmentioning

confidence: 99%

Protein Phosphatase 2C Inactivates F-actin Binding of Human Platelet Moesin

Hishiya¹,

Ohnishi²,

Tamura³

et al. 1999

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

During activation of platelets by thrombin phosphorylation of Thr558 in the C-terminal domain of the membrane-F-actin linking protein moesin increases transiently, and this correlates with protrusion of filopodial structures. Calyculin A enhances phosphorylation of moesin by inhibition of phosphatases. To measure this moesin-specific activity, a nonradioactive enzymelinked immunosorbent assay method was developed with the synthetic peptide Cys-Lys 555 -Tyr-Lys-Thr(P)-Leu-Arg 560 coupled to bovine serum albumin as the substrate and moesin phosphorylation state-specific polyclonal antibodies for the detection and quantitation of dephosphorylation. Calyculin A-sensitive and -insensitive protein-threonine phosphatase activities were detected in platelet lysates and separated by DEAE-cellulose chromatography. The calyculin A-sensitive enzyme was identified as a type 1 protein phosphatase. The calyculin A-insensitive enzyme activity was purified to homogeneity by phenyl-Sepharose, protamine-, and phosphonic acid peptide-agarose chromatography and characterized biochemically and immunologically as a 53-kDa protein(s) and a type 2C protein phosphatase (PP2C). Phosphorylation of Thr 558 is necessary for Factin binding of moesin in vitro. The purified enzyme, as well as bacterially made PP2C␣ and PP2C␤, efficiently dephosphorylate(s) highly purified platelet phosphomoesin. This reverses the activating effect of phosphorylation, and moesin no longer co-sediments with actin filaments. In vivo, regulation of these phosphatase activities are likely to influence dynamic interactions between the actin cytoskeleton and membrane constituents linked to moesin.

show abstract

Section: Discussionmentioning

confidence: 99%

Protein Phosphatase 2C Inactivates F-actin Binding of Human Platelet Moesin

Hishiya¹,

Ohnishi²,

Tamura³

et al. 1999

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

show abstract

“…PP2C is distinct from the other three major PPs because of its absolute requirement for Mg# + or Mn# + and because its amino acid sequence shows little similarity to those of other PPs [5]. Recent studies on the function of mammalian PP2C have suggested that it participates in the regulation of AMP-activated protein kinase [6] and Ca# + \calmodulin-dependent protein kinase II [7] activities and regulation of the DNA-repair system [8]. Molecular genetic analysis of the function of PP2C in plants has revealed that Arabidopsis ABI1 protein has an EF-hand Ca# +binding site and a PP2C-related sequence in its N-terminal and C-terminal domains respectively, and is involved in intracellular Abbreviations used : PP, protein serine/threonine phosphatase ; GST, glutathione S-transferase ; ORF, open reading frame ; HA, haemagglutinin ; NLS, nuclear localization signal.…”

Section: Introductionmentioning

confidence: 99%

Mutational analysis of the domain structure of mouse protein phosphatase 2Cβ

Kusuda

Kobayashi

Ikeda

et al. 1998

Biochemical Journal

Self Cite

View full text Add to dashboard Cite

The structures of five distinct isoforms of mammalian protein phosphatase 2Cbeta (PP2Cbeta-1, -2, -3, -4 and -5) have previously been found to differ only at their C-terminal regions. In the present study, we performed mutational analysis of recombinant mouse PP2Cbeta-1 to determine the functional domains of the molecule and elucidate the biochemical significance of the structural differences in the isoforms. Differences in affinity for [32P]phosphohistone but not for [32P]phosphocasein were observed among the five PP2Cbeta isoforms. Deletion of 12 amino acids from the C-terminal end, which form a unique sequence for PP2Cbeta-1, caused a 35% loss of activity against [32P]phosphohistone but no loss of activity against [32P]phosphocasein. Deletion of up to 78 amino acids from this end did not cause any further alteration in activity, whereas deletion of 100 amino acids totally eliminated the activity against both [32P]phosphohistone and [32P]phosphocasein. On the other hand, deletion of 11 amino acids from the N-terminal end caused a 97% loss of enzyme activity, and further deletions caused a total loss of activity. Substitution of any of the six specific amino acids among 16 tested in this study, which were located among the 250 N-terminal residues, caused 98-100% loss of enzyme activity. Among these amino acids, three (Glu-38, -60 and -243) have recently been reported to be essential for the binding of metal ions in the catalytic site of the PP2C molecule [Das, Helps, Cohen and Barford (1996) EMBO J. 15, 6798-6809]. These observations indicate that PP2Cbeta is composed of at least two distinct functional domains, an N-terminal catalytic domain of about 310 amino acids and the remaining C-terminal domain, which is involved in determination of substrate specificity.

show abstract

“…Genes encoding PP2C homologs have also been isolated from other eukaryotic cells [8 14]. Recent investigations of the functions of mammalian PP2C have revealed that PP2C participates in the regulation of AMP-activated protein kinase activity [15], Ca2+-dependent signal transduction [16] and DNA repair systems [17]. However, the specificity of the physiological functions of each PP2C isoform in mammalian cells has yet to be elucidated.…”

Section: Introductionmentioning

confidence: 99%