Characterization of Candida albicans orthologue of the Saccharomyces cerevisiae signal-peptidase-subunit encoding gene SPC3.
The Candida albicans orthologue of the SPC3 gene, which encodes one of the subunits essential for the activity of the signal peptidase complex in Saccharomyces cerevisiae, was isolated by complementation of a thermosensitive mutation in the S. cerevisiae SEC61 gene. The cloned gene (CaSPC3) encodes a putative protein of 192 amino acids that contains one potential membrane-spanning region and shares significant homology with the corresponding products from mammalian (Spc22/23p) and yeast (Spc3p) cells. CaSPC3 is essential for cell viability, since a hemizygous strain containing a single copy of CaSPC3 under control of the methionine-repressible MET3 promoter did not grow in the presence of methionine and cysteine. The cloned gene could rescue the phenotype associated with a spc3 mutation in S. cerevisiae, indicating that it is the true C. albicans orthologue of SPC3. However, in contrast with results previously described for its S. cerevisiae orthologue, CaSPC3 was not able to complement the thermosensitive growth associated with a mutation in the SEC11 gene. The heterologous complementation of the sec61 mutant suggests that Spc3p could play a role in the interaction that it is known to occur between the translocon (Sec61 complex) and the signal peptidase complex, at the endoplasmic reticulum membrane.
Departamento de Microbiología y Biología Celular, Facultad de Farmacia, Universidad de La Laguna, 38071 La Laguna, Tenerife, Spain.
José M
JM
De La Rosa
José M
JM
González
Fernando
F
Gutiérrez
Teresa
T
Ruíz
Luis
L
Rodríguez
D000595:Amino Acid Sequence; D001483:Base Sequence; D015153:Blotting, Western; D002176:Candida albicans / Q000201:enzymology* / Q000235:genetics; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D015723:Gene Library; D005800:Genes, Fungal / Q000502:physiology*; D005816:Genetic Complementation Test; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D021382:Protein Sorting Signals / Q000502:physiology*; D021122:Protein Subunits; D016415:Sequence Alignment; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D013499:Surface Properties; D014170:Transformation, Genetic / Q000502:physiology; D043324:beta-Fructofuranosidase / Q000378:metabolism
D004271:DNA, Fungal; D008565:Membrane Proteins; D021382:Protein Sorting Signals; D021122:Protein Subunits; D043324:beta-Fructofuranosidase; D012697:Serine Endopeptidases; C026515:type I signal peptidase