Diverse proteins homologous to inositol monophosphatase

Neuwald, Andrew F.; York, John D.; Majerus, Philip W.

doi:10.1016/0014-5793(91)81332-3

Cited by 52 publications

(53 citation statements)

References 10 publications

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“…The evolutionary distances among the representative seven members of the inositol monophosphatase family (26) have been calculated by the method of Hein (13), and the resulting phylogenetic tree is illustrated in Fig. 1.…”

Section: Resultsmentioning

confidence: 99%

“…The seven members that were used for calculation included SuhB, bovine inositol monophosphatase (4), CysQ (which is involved in sulfate assimilation in E. coli) (25), Qut-G and Qa-X (which are hypothetical gene products from open reading frames in Aspergillus nidulans and Neurospora crassa, respectively) (8,12), bovine inositol polyphosphate 1-phosphatase (which hydrolyzes the 1-position phosphate of inositol 1,3,4-triphosphate and inositol 1,4-bisphosphate) (41), and Met22 (which is involved in salt tolerance in Saccharomyces cerevisiae) (9). Not only do these proteins share two sequence motifs (26), but the similarity is found throughout the length of the SuhB sequence (except for long insertions in inositol polyphosphate 1-phosphatase, Met22, Qut-G, and Qa-X). Although SuhB and bovine inositol monophosphatase belong to different kingdoms, the phylogenetic analysis showed that SuhB has a close relationship to the mammalian inositol monophosphatases (the overall amino acid identity is approximately 30%).…”

Section: Resultsmentioning

confidence: 99%

“…The suhB gene encodes a protein of 268 amino acids (40), and the primary structure of its translated product shows a high level of similarity to proteins of the mammalian inositol monophosphatase family (26). Inositol monophosphatase (EC 3.1.…”

mentioning

confidence: 99%

“…3.25) hydrolyzes the ester bond of myo-inositol 1(or 4)-phosphate to release myo-inositol plus P i and plays a key role in the biosyntheses of inositol phosphates and inositol phospholipids that are involved in signal transduction in mammalian and plant cells (for reviews, see references 5 and 21). Genes homologous to inositol monophosphatase have been identified in bacteria, lower eukaryotes, and higher eukaryotes (9,26), indicating that this family of genes has evolved in diverse ways from a common ancestral gene that may have originated before the separation of eukaryotes and prokaryotes.…”

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Inositol monophosphatase activity from the Escherichia coli suhB gene product

et al. 1995

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The suhB gene is located at 55 min on the Escherichia coli chromosome and encodes a protein of 268 amino acids. Mutant alleles of suhB have been isolated as extragenic suppressors for the protein secretion mutation (secY24), the heat shock response mutation (rpoH15), and the DNA synthesis mutation (dnaB121) (K. Shiba, K. Ito, and T. Yura, J. Bacteriol. 160:696-701, 1984; R. Yano, H. Nagai, K. Shiba, and T. Yura, J. Bacteriol. 172:2124-2130, 1990; S. Chang, D. Ng, L. Baird, and C. Georgopoulos, J. Biol. Chem. 266:3654-3660, 1991). These mutant alleles of suhB cause cold-sensitive cell growth, indicating that the suhB gene is essential at low temperatures. Little work has been done, however, to elucidate the role of the product of suhB in a normal cell and the suppression mechanisms of the suhB mutations in the aforementioned mutants. The sequence similarity shared between the suhB gene product and mammalian inositol monophosphatase has prompted us to test the inositol monophosphatase activity of the suhB gene product. We report here that the purified SuhB protein showed inositol monophosphatase activity. The kinetic parameters of SuhB inositol monophosphatase (K m ‫؍‬ 0.071 mM; V max ‫؍‬ 12.3 mol/min per mg) are similar to those of mammalian inositol monophosphatase. The ssyA3 and suhB2 mutations, which were isolated as extragenic suppressors for secY24 and rpoH15, respectively, had a DNA insertion at the 5 proximal region of the suhB gene, and the amount of SuhB protein within mutant cells decreased. The possible role of suhB in E. coli is discussed.The suhB gene was first identified as the locus for the ssyA3(Cs) mutation that was isolated as an extragenic suppressor for the secY24(Ts) mutant (31). The ssyA3 mutation restored the defect in protein secretion caused by the secY24 mutation (33) and rescued the temperature-sensitive cell growth of secY24 mutant cells. The ssyA3 mutation caused cold-sensitive cell growth by itself and impaired protein synthesis was observed in the ssyA3 mutant at low temperatures (31). The cold-sensitive growth of the ssyA3 mutant was rescued by introduction of the wild-type copy of suhB, indicating that ssyA3 is a mutant allele of suhB (40). The suhB2(Cs) mutation is another allele of suhB and was isolated as an extragenic suppressor of the rpoH15(Ts) mutation. The rpoH15 mutant gene produces an altered 32 protein and causes a defect in the induction of heat shock proteins at higher temperatures (42). The suhB2(Cs) mutation rescued the temperature-sensitive cell growth of the rpoH15 mutant and partially restored heat shock induction in the mutant cell (40). A coldsensitive mutation was also mapped in the suhB locus as an extragenic suppressor for the dnaB121(Ts) mutation that inhibits replication of phage (2). Thus, mutant alleles of suhB have effects on diverse cell activities, including protein export, stress response, and DNA replication.The suhB gene encodes a protein of 268 amino acids (40), and the primary structure of its translated product shows a high level of similarity t...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Inositol monophosphatase activity from the Escherichia coli suhB gene product

et al. 1995

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“…Two additional IMP genes were isolated based on their similarity to LelMP7. All of these genes share four domains that are found not only in known IMP proteins but also in several proteins of unknown biochemical function (see Neuwald et al, 1994) as well as in the yeast HAL2 protein, which encodes a bisphosphate nucleotidase that is involved in salt tolerance (Murguia et al, 1995). Expression of the LelMP genes in Escherichia coli confirmed that these genes indeed encode IMPs: all were able to dephosphorylate l%-labeled inositol 1-phosphate.…”

Section: In Thls Issuementioning

confidence: 92%