Inhibition of an archaeal protein phosphatase activity by okadaic acid, microcystin‐LR, or calyculin A

Oxenrider, Keith A.; Rasche, Madeline E.; Thorsteinsson, Marc V.; Kennelly, Peter J.

doi:10.1016/0014-5793(93)80355-x

Cited by 18 publications

(14 citation statements)

References 22 publications

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“…The genes encoding PP1-arch1, PP1-arch2, and Py-PP1 were cloned from Sulfolobus solfataricus (216,252), Methanosarcina thermophila TM-1 (321,403), and Pyrodictium abyssi TAG11 (268), respectively. In addition, other archaeal PPP family phosphorylases have been predicted following analysis of genome sequences, relying on the presence of conserved sequence motifs (24,215).…”

Section: Archaeal Protein Kinases and Phosphatasesmentioning

confidence: 99%

“…However, despite their sequence similarities to eucaryal PPP family members, archaeal PPP family protein serine/threonine phosphatases display a combination of eucaryal and bacterial features (215). Like their eucaryal counterparts, the archaeal enzymes specifically act upon proteinbound phosphoserine and phosphothreonine residues and, in the cases of PP1-arch2 and Py-PP1, are inhibited by toxic secondary metabolites such as okadaic acid (268,321,403). In contrast, the three archaeal PPP family members require the addition of metal ions such as Mn 2ϩ for activity, as is the case for bacterial PPP family protein serine/threonine phosphatases (391).…”

Section: Archaeal Protein Kinases and Phosphatasesmentioning

confidence: 99%

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Posttranslational Protein Modification inArchaea

Eichler

Adams

2005

Microbiol Mol Biol Rev

194

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One of the first hurdles to be negotiated in the postgenomic era involves the description of the entire protein content of the cell, the proteome. Such efforts are presently complicated by the various posttranslational modifications that proteins can experience, including glycosylation, lipid attachment, phosphorylation, methylation, disulfide bond formation, and proteolytic cleavage. Whereas these and other posttranslational protein modifications have been well characterized in Eucarya and Bacteria, posttranslational modification in Archaea has received far less attention. Although archaeal proteins can undergo posttranslational modifications reminiscent of what their eucaryal and bacterial counterparts experience, examination of archaeal posttranslational modification often reveals aspects not previously observed in the other two domains of life. In some cases, posttranslational modification allows a protein to survive the extreme conditions often encountered by Archaea. The various posttranslational modifications experienced by archaeal proteins, the molecular steps leading to these modifications, and the role played by posttranslational modification in Archaea form the focus of this review

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Section: Archaeal Protein Kinases and Phosphatasesmentioning

confidence: 99%

Section: Archaeal Protein Kinases and Phosphatasesmentioning

confidence: 99%

Posttranslational Protein Modification inArchaea

Eichler

Adams

2005

Microbiol Mol Biol Rev

194

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“…The effect of protein phosphatase and other phosphomonoesterase inhibitors (11,14,16) on the activity of ST-PrpA and ST-PrpB was also examined (data not shown). At the concentrations tested, pyrophosphate, the chelating agent EDTA, the nonspecific phosphatase inhibitor NaF, and the tyrosine phosphatase inhibitor vanadate inhibited Ͼ90% of activity from either enzyme with […”

Section: Resultsmentioning

confidence: 99%

“…Homologs of PPP phosphatases can be discerned in many bacterial and archaeal genomes (for reviews, see references 8 and 17). All bacterial PPP phosphatases characterized to date require Mn 2ϩ for maximal activation (7,10,(12)(13)(14)(15)(16)(18)(19)(20). To investigate the role of Mn 2ϩ further, we have cloned, purified, and characterized the two PPP phosphatase homologs evident in the extant genome of serovar Typhimurium.…”

Section: Salmonella Enterica Serovar Typhimurium Requires Mnmentioning

confidence: 99%

The PPP-Family Protein Phosphatases PrpA and PrpB of Salmonella enterica Serovar Typhimurium Possess Distinct Biochemical Properties

2001

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Salmonella enterica serovar Typhimurium requires Mn2؉ , but only a few Mn 2؉ -dependent enzymes have been identified from bacteria. To characterize Mn 2؉ -dependent enzymes from serovar Typhimurium, two putative PPP-family protein phosphatase genes were cloned from serovar Typhimurium and named prpA and prpB. Their DNA-derived amino acid sequences showed 61% identity to the corresponding Escherichia coli proteins and 41% identity to each other. Each phosphatase was expressed in E. coli and purified to near electrophoretic homogeneity. Both PrpA and PrpB absolutely required a divalent metal for activity. As with other phosphatases of this class, Mn 2؉ had the highest affinity and stimulated the greatest activity. The apparent K a of PrpA for Mn 2؉ of 65 M was comparable to that for other bacterial phosphatases, but PrpB had a much higher affinity for Mn 2؉ (1.3 M). The pH optima were pH 6.5 for PrpA and pH 8 for PrpB, while the optimal temperatures were 45 to 55°C for PrpA and 30 to 37°C for PrpB. Each phosphatase could hydrolyze phosphorylated serine, threonine, or tyrosine residues, but their relative specific activities varied with the specific substrate tested. These differences suggest that each phosphatase is used by serovar Typhimurium under different growth or environmental conditions such as temperature or acidity.MntH, the Salmonella enterica serovar Typhimurium ortholog of the eukaryotic NRAMP proteins (natural resistanceassociated macrophage protein), is a highly selective H ϩ -stimulated Mn 2ϩ transporter (6). Subsequently, the mammalian NRAMP1 protein, expressed in monocytes and macrophages, was shown to mediate marked changes in intracellular Mn 2ϩ in macrophages (5). Transcription of mntH in serovar Typhimurium is induced by hydrogen peroxide and cation starvation, and mutation of mntH makes serovar Typhimurium cells more sensitive to killing by peroxide. These data suggest that Mn 2ϩ is required for maintenance of some physiological functions and that Mn 2ϩ could play a role in virulence, especially in resistance to reactive oxygen species (6). Any role for Mn 2ϩ is presumably mediated by its use as an enzyme cofactor. Surprisingly, very few known enzymes are known to be Mn 2ϩ dependent. In an effort to understand the role of Mn 2ϩ in cell function and pathogenesis, we have begun to characterize each of the few known Mn 2ϩ -cofactored enzymes. One such family is the PPP class of protein phosphatases (2,8,17).PPP phosphatases are metalloenzymes that include the catalytic subunits of mammalian PP1, PP2A, PP2B, and related protein phosphatases. Two divalent metal ions in their active sites catalyze a single-step dephosphorylation reaction. In eukaryotes, PPP phosphatases are involved in regulating multiple cellular functions such as cell division, glycogen metabolism, and muscle contraction. Homologs of PPP phosphatases can be discerned in many bacterial and archaeal genomes (for reviews, see references 8 and 17). All bacterial PPP phosphatases characterized to date require Mn 2ϩ for maximal activat...

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“…Sensitivity to these and other toxins, such as okadaic acid, is so highly conserved among eukaryotic PP1 and PP2A that it serves as a criterion for the identification of these enzymes in cell extracts (5). Moderate sensitivity to microcystin-LR extends to homologs recently identified in members of the Archaea such as Methanosarcina thermophila TM-1 (6,7) and Pyrodictium abyssi TAG11 (8).…”

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confidence: 99%

Cyanobacterial PPP Family Protein Phosphatases Possess Multifunctional Capabilities and Are Resistant to Microcystin-LR

Shi

Carmichael

Kennelly

1999

Journal of Biological Chemistry

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The structural gene for a putative PPP family proteinserine/threonine phosphatase from the microcystin-producing cyanobacterium Microcystis aeruginosa PCC 7820, pp1-cyano1, was cloned. The sequence of the predicted gene product, PP1-cyano1, was 98% identical to that of the predicted product of an open reading frame, pp1-cyano2, from a cyanobacterium that does not produce microcystins, M. aeruginosa UTEX 2063. By contrast, PP1-cyano1 displayed less than 20% identity with other PPP family protein phosphatases from eukaryotic, archaeal, or other bacterial organisms. PP1-cyano1 and PP1-cyano2 were expressed in Escherichia coli and purified to homogeneity. Both enzymes exhibited divalent metal dependent phosphohydrolase activity in vitro toward phosphoserine-and phosphotyrosine-containing proteins and 3-phosphohistidine-and phospholysine-containing amino acid homopolymers. This multifunctional potential also was apparent in samples of PP1-cyano1 and PP1-cyano2 isolated from M. aeruginosa. Catalytic activity was insensitive to okadaic acid or the cyanobacterially produced cyclic heptapeptide, microcystin-LR, both potent inhibitors of mammalian PP1 and PP2A. PP1-cyano1 and PP1-cyano2 displayed diadenosine tetraphosphatase activity in vitro. Diadenosine tetraphosphatases share conserved sequence features with PPP family protein phosphatases. The diadenosine tetraphosphatase activity of PP1-cyano1 and PP1-cyano2 confirms that these enzymes share a common catalytic mechanism.Strains of the cyanobacterium Microcystis aeruginosa sp. synthesize the cyclic heptapeptide microcystin-LR, a potent toxin toward humans and other animals (1, 2). In eukaryotes, the immediate targets of microcystin-LR are the structurally homologous catalytic subunits of the protein-serine/threonine phosphatases PP2A and PP1 1 (3), to which it binds with nanomolar or near nanomolar affinity, respectively (4). Sensitivity to these and other toxins, such as okadaic acid, is so highly conserved among eukaryotic PP1 and PP2A that it serves as a criterion for the identification of these enzymes in cell extracts (5). Moderate sensitivity to microcystin-LR extends to homologs recently identified in members of the Archaea such as Methanosarcina thermophila TM-1 (6, 7) and Pyrodictium abyssi TAG11 (8).Recently, the presence of open reading frames potentially encoding PP1/2A-like, also known as the PPP family (9), protein phosphatases has been reported in two strains of M. aeruginosa, the microcystin-producing strain M. aeruginosa PCC 7820 and the non-producing strain M. aeruginosa UTEX 2063 (10). These open reading frames have been designated pp1-cyano1 and pp1-cyano2, respectively. Given the observation that microcystins accumulate within the interior of toxin-producing cyanobacteria (11), and the near absolute conservation of sensitivity to these compounds by members of the PP1/2A superfamily (5), how do microcystin-producing cyanobacteria protect themselves from the action of endogenous toxins against their presumptive PP1/ 2A-like protein phosphatases? It ...

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Inhibition of an archaeal protein phosphatase activity by okadaic acid, microcystin‐LR, or calyculin A

Cited by 18 publications

References 22 publications

Posttranslational Protein Modification inArchaea

Posttranslational Protein Modification inArchaea

The PPP-Family Protein Phosphatases PrpA and PrpB of Salmonella enterica Serovar Typhimurium Possess Distinct Biochemical Properties

Cyanobacterial PPP Family Protein Phosphatases Possess Multifunctional Capabilities and Are Resistant to Microcystin-LR

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