Functional characterization of the MKC1 gene of Candida albicans, which encodes a mitogen-activated protein kinase homolog related to cell integrity.
Mitogen-activated protein (MAP) kinases represent a group of serine/threonine protein kinases playing a central role in signal transduction processes in eukaryotic cells. Using a strategy based on the complementation of the thermosensitive autolytic phenotype of slt2 null mutants, we have isolated a Candida albicans homolog of Saccharomyces cerevisiae MAP kinase gene SLT2 (MPK1), which is involved in the recently outlined PKC1-controlled signalling pathway. The isolated gene, named MKC1 (MAP kinase from C. albicans), coded for a putative protein, Mkc1p, of 58,320 Da that displayed all the characteristic domains of MAP kinases and was 55% identical to S. cerevisiae Slt2p (Mpk1p). The MKC1 gene was deleted in a diploid Candida strain, and heterozygous and homozygous strains, in both Ura+ and Ura- backgrounds, were obtained to facilitate the analysis of the function of the gene. Deletion of the two alleles of the MKC1 gene gave rise to viable cells that grew at 28 and 37 degrees C but, nevertheless, displayed a variety of phenotypic traits under more stringent conditions. These included a low growth yield and a loss of viability in cultures grown at 42 degrees C, a high sensitivity to thermal shocks at 55 degrees C, an enhanced susceptibility to caffeine that was osmotically remediable, and the formation of a weak cell wall with a very low resistance to complex lytic enzyme preparations. The analysis of the functions downstream of the MKC1 gene should contribute to understanding of the connection of growth and morphogenesis in pathogenic fungi.
Navarro-García
F
F
Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense, Spain.
Sánchez
M
M
Pla
J
J
Nombela
C
C
D000595:Amino Acid Sequence; D001483:Base Sequence; D002110:Caffeine / Q000494:pharmacology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics* / Q000378:metabolism; D002176:Candida albicans / Q000187:drug effects / Q000201:enzymology / Q000235:genetics* / Q000502:physiology*; D002473:Cell Wall / Q000502:physiology; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D005800:Genes, Fungal / Q000235:genetics*; D005966:Glucuronidase / Q000494:pharmacology; D006358:Hot Temperature / Q000009:adverse effects; D020928:Mitogen-Activated Protein Kinases; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000494:pharmacology; D005810:Multigene Family / Q000235:genetics; D009996:Osmotic Fragility; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D013429:Sulfatases / Q000494:pharmacology
D005656:Fungal Proteins; D009097:Multienzyme Complexes; D029701:Saccharomyces cerevisiae Proteins; C023059:glusulase; D002110:Caffeine; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C092603:MKC1 protein, Candida albicans; D020928:Mitogen-Activated Protein Kinases; C072724:SLT2 protein, S cerevisiae; D013429:Sulfatases; D005966:Glucuronidase