The Candida albicans pH-regulated KER1 gene encodes a lysine/glutamic-acid-rich plasma-membrane protein that is involved in cell aggregation

A. Galan, M. Casanova, A. Murgui, Donna Margaret MacCallum, Frank Christopher Odds, Neil Andrew Robert Gow, J. P. Martínez

Research output: Contribution to journalArticle

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Abstract

Immunoscreening of a Candida albicans cDNA library with a polyclonal germ-tube-specific antibody (pAb anti-gt) resulted in the isolation of a gene encoding a lysine/glutamic-acid-rich protein, which was consequently designated KER1. The nucleotide and deduced amino acid sequences of this gene displayed no significant homology with any other known sequence. KER1 encodes a 134 kDa lysine (14.5%)/glutamic acid (16.7%) protein (Ker1p) that contains two potential transmembrane segments. KER1 was expressed in a pH-conditional manner, with maximal expression at alkaline pH and lower expression at pH 4.0, and was regulated by RIM101. A Deltaker1/Deltaker1 null mutant grew normally but was hyperflocculant under germ-tube-inducing conditions, yet this behaviour was also observed in stationary-phase cells grown under other incubation conditions. Western blotting analysis of different subcellular fractions, using as a probe a monospecific polyclonal antibody raised against a highly antigenic domain of Ker1p (pAb anti-Ker1p), revealed the presence of a 134 kDa band in the purified plasma-membrane fraction from the wild-type strain that was absent in the homologous preparation from Deltaker1/Deltaker1 mutant. The pattern of cell-wall protein and mannoprotein species released by digestion with beta-glucanases, reactive towards pAbs anti-gt and anti-Ker1p, as well as against concanavalin A, was also different in the Deltaker1/Deltaker1 mutant. Mutant strains also displayed an increased cell-surface hydrophobicity and sensitivity to Congo red and Calcofluor white. Overall, these findings indicate that the mutant strain was affected in cell-wall composition and/or structure. The fact that the ker1 mutant had attenuated virulence in systemic mouse infections suggests that this surface protein is also important in host-fungus interactions.

Original languageEnglish
Pages (from-to)2641-2651
Number of pages11
JournalMicrobiology
Volume150
Issue numberPt 8
DOIs
Publication statusPublished - 2004

Keywords

  • saccharomyces-cerevisiae
  • yeast-cells
  • surface hydrophobicity
  • wall mannoproteins
  • molecular analysis
  • ambient PH
  • expression
  • identification
  • cloning
  • morphogenesis

Cite this

The Candida albicans pH-regulated KER1 gene encodes a lysine/glutamic-acid-rich plasma-membrane protein that is involved in cell aggregation. / Galan, A.; Casanova, M.; Murgui, A.; MacCallum, Donna Margaret; Odds, Frank Christopher; Gow, Neil Andrew Robert; Martínez, J. P.

In: Microbiology , Vol. 150, No. Pt 8, 2004, p. 2641-2651.

Research output: Contribution to journalArticle

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abstract = "Immunoscreening of a Candida albicans cDNA library with a polyclonal germ-tube-specific antibody (pAb anti-gt) resulted in the isolation of a gene encoding a lysine/glutamic-acid-rich protein, which was consequently designated KER1. The nucleotide and deduced amino acid sequences of this gene displayed no significant homology with any other known sequence. KER1 encodes a 134 kDa lysine (14.5{\%})/glutamic acid (16.7{\%}) protein (Ker1p) that contains two potential transmembrane segments. KER1 was expressed in a pH-conditional manner, with maximal expression at alkaline pH and lower expression at pH 4.0, and was regulated by RIM101. A Deltaker1/Deltaker1 null mutant grew normally but was hyperflocculant under germ-tube-inducing conditions, yet this behaviour was also observed in stationary-phase cells grown under other incubation conditions. Western blotting analysis of different subcellular fractions, using as a probe a monospecific polyclonal antibody raised against a highly antigenic domain of Ker1p (pAb anti-Ker1p), revealed the presence of a 134 kDa band in the purified plasma-membrane fraction from the wild-type strain that was absent in the homologous preparation from Deltaker1/Deltaker1 mutant. The pattern of cell-wall protein and mannoprotein species released by digestion with beta-glucanases, reactive towards pAbs anti-gt and anti-Ker1p, as well as against concanavalin A, was also different in the Deltaker1/Deltaker1 mutant. Mutant strains also displayed an increased cell-surface hydrophobicity and sensitivity to Congo red and Calcofluor white. Overall, these findings indicate that the mutant strain was affected in cell-wall composition and/or structure. The fact that the ker1 mutant had attenuated virulence in systemic mouse infections suggests that this surface protein is also important in host-fungus interactions.",
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T1 - The Candida albicans pH-regulated KER1 gene encodes a lysine/glutamic-acid-rich plasma-membrane protein that is involved in cell aggregation

AU - Galan, A.

AU - Casanova, M.

AU - Murgui, A.

AU - MacCallum, Donna Margaret

AU - Odds, Frank Christopher

AU - Gow, Neil Andrew Robert

AU - Martínez, J. P.

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AB - Immunoscreening of a Candida albicans cDNA library with a polyclonal germ-tube-specific antibody (pAb anti-gt) resulted in the isolation of a gene encoding a lysine/glutamic-acid-rich protein, which was consequently designated KER1. The nucleotide and deduced amino acid sequences of this gene displayed no significant homology with any other known sequence. KER1 encodes a 134 kDa lysine (14.5%)/glutamic acid (16.7%) protein (Ker1p) that contains two potential transmembrane segments. KER1 was expressed in a pH-conditional manner, with maximal expression at alkaline pH and lower expression at pH 4.0, and was regulated by RIM101. A Deltaker1/Deltaker1 null mutant grew normally but was hyperflocculant under germ-tube-inducing conditions, yet this behaviour was also observed in stationary-phase cells grown under other incubation conditions. Western blotting analysis of different subcellular fractions, using as a probe a monospecific polyclonal antibody raised against a highly antigenic domain of Ker1p (pAb anti-Ker1p), revealed the presence of a 134 kDa band in the purified plasma-membrane fraction from the wild-type strain that was absent in the homologous preparation from Deltaker1/Deltaker1 mutant. The pattern of cell-wall protein and mannoprotein species released by digestion with beta-glucanases, reactive towards pAbs anti-gt and anti-Ker1p, as well as against concanavalin A, was also different in the Deltaker1/Deltaker1 mutant. Mutant strains also displayed an increased cell-surface hydrophobicity and sensitivity to Congo red and Calcofluor white. Overall, these findings indicate that the mutant strain was affected in cell-wall composition and/or structure. The fact that the ker1 mutant had attenuated virulence in systemic mouse infections suggests that this surface protein is also important in host-fungus interactions.

KW - saccharomyces-cerevisiae

KW - yeast-cells

KW - surface hydrophobicity

KW - wall mannoproteins

KW - molecular analysis

KW - ambient PH

KW - expression

KW - identification

KW - cloning

KW - morphogenesis

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DO - 10.1099/mic.0.26339-0

M3 - Article

VL - 150

SP - 2641

EP - 2651

JO - Microbiology

JF - Microbiology

SN - 1350-0872

IS - Pt 8

ER -