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Identification and characterization of an essential family of inositol polyphosphate 5-phosphatases (INP51, INP52 and INP53 gene products) in the yeast Saccharomyces cerevisiae.

Publication ,  Journal Article
Stolz, LE; Huynh, CV; Thorner, J; York, JD
Published in: Genetics
April 1998

We recently demonstrated that the S. cerevisiae INP51 locus (YIL002c) encodes an inositol polyphosphate 5-phosphatase. Here we describe two related yeast loci, INP52 (YNL106c) and INP53 (YOR109w). Like Inp51p, the primary structures of Inp52p and Inp53p resemble the mammalian synaptic vesicle-associated protein, synaptojanin, and contain a carboxy-terminal catalytic domain and an amino-terminal SAC1-like segment. Inp51p (108 kD), Inp52p (136 kD) and Inp53p (124 kD) are membrane-associated. Single null mutants (inp51, inp52, or inp53) are viable. Both inp51 inp52 and inp52 inp53 double mutants display compromised cell growth, whereas an inp51 inp53 double mutant does not. An inp51 inp52 inp53 triple mutant is inviable on standard medium, but can grow weakly on media supplemented with an osmotic stabilizer (1 M sorbitol). An inp51 mutation, and to a lesser degree an inp52 mutation, confers cold-resistant growth in a strain background that cannot grow at temperatures below 15 degrees. Analysis of inositol metabolites in vivo showed measurable accumulation of phosphatidylinositol 4,5-bisphosphate in the inp51 mutant. Electron microscopy revealed plasma membrane invaginations and cell wall thickening in double mutants and the triple mutant grown in sorbitol-containing medium. A fluorescent dye that detects endocytic and vacuolar membranes suggests that the vacuole is highly fragmented in inp51 inp52 double mutants. Our observations indicate that Inp51p, Inp52p, and Inp53p have distinct functions and that substrates and/or products of inositol polyphosphate 5-phosphatases may have roles in vesicle trafficking, membrane structure, and/or cell wall formation.

Duke Scholars

Published In

Genetics

DOI

ISSN

0016-6731

Publication Date

April 1998

Volume

148

Issue

4

Start / End Page

1715 / 1729

Location

United States

Related Subject Headings

  • Saccharomyces cerevisiae
  • Phosphoric Monoester Hydrolases
  • Phosphatidylinositol 4,5-Diphosphate
  • Molecular Sequence Data
  • Inositol Polyphosphate 5-Phosphatases
  • Gene Deletion
  • Developmental Biology
  • Amino Acid Sequence
  • 3105 Genetics
  • 3101 Biochemistry and cell biology
 

Citation

APA
Chicago
ICMJE
MLA
NLM

Published In

Genetics

DOI

ISSN

0016-6731

Publication Date

April 1998

Volume

148

Issue

4

Start / End Page

1715 / 1729

Location

United States

Related Subject Headings

  • Saccharomyces cerevisiae
  • Phosphoric Monoester Hydrolases
  • Phosphatidylinositol 4,5-Diphosphate
  • Molecular Sequence Data
  • Inositol Polyphosphate 5-Phosphatases
  • Gene Deletion
  • Developmental Biology
  • Amino Acid Sequence
  • 3105 Genetics
  • 3101 Biochemistry and cell biology