title: Identification of a putative response regulator two-component phosphorelay gene ( CaSSK1) from Candida albicans.
abstract: We have identified and analysed a putative response regulator two-component gene (CaSSK1) from Candida albicans and its encoding protein (CaSsk1p). CaSSK1 has an open reading frame of 2022 bp. In the promotor region of CaSSK1 a short sequence is found that matches the consensus sequence of the stress response elements (STRE) from Saccharomyces cerevisiae. CaSSK1 is located on chromosome 1 and is expressed in either yeast or mycelial phases of C. albicans. CaSSK1 encodes a 674 amino acid protein (CaSsk1p) with an estimated molecular mass of 73.5 kDa and a basic isoelectric point (pI 9.5). It has a tripeptide (NKA) located in its C-terminus, which resembles the peroxisomal signalling target type 1 sequence (PST1) of most of the peroxisomal matrix proteins. A homology search of CaSsk1p with other proteins in databases showed that the C-terminus of CaSsk1p exhibits the greatest similarity with the C-terminus of Ssk1p and Mcs4 from Saccharomyces cerevisiae and Schizosaccharomyces pombe, respectively. The response regulator domain of CaSsk1p contains the motifs that are characteristic of all response regulators, including the conserved aspartate and lysine residues as well as the putative aspartate, which is phosphorylated by a phosphohistidine residue. Finally, in spite of the structural similarities among CaSsk1p, Ssk1p and Mcs4, CaSsk1p does not seem to exhibit functional homology with these proteins.
authors.affiliation: Department of Microbiology and Immunology, Georgetown University Medical Center, 3900 Reservoir Road NW, Washington, DC 20007-2197, USA. caleraaj@medlib.georgetown.edu
authors.forename: J A
authors.initials: JA
authors.lastname: Calera
authors.forename: R A
authors.initials: RA
authors.lastname: Calderone
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002176:Candida albicans / Q000235:genetics* / Q000254:growth & development; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics; D015825:Chromosomes, Fungal / Q000235:genetics; D003001:Cloning, Molecular; D016384:Consensus Sequence / Q000235:genetics; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D005800:Genes, Fungal / Q000235:genetics / Q000502:physiology; D005816:Genetic Complementation Test; D007526:Isoelectric Point; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009154:Mutation; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces / Q000235:genetics / Q000254:growth & development; D029702:Schizosaccharomyces pombe Proteins; D017386:Sequence Homology, Amino Acid
chemical_list: D018797:Cell Cycle Proteins; D005656:Fungal Proteins; C105788:Mcs4 protein, S pombe; D012333:RNA, Messenger; C087199:SSK1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins