title: Dolichol phosphate mannose synthase from the pathogenic yeast Candida albicans is a multimeric enzyme.
abstract: BACKGROUND
  Dolichol phosphate mannose synthase (DPMS) is a key enzyme in N- and O-linked glycosylations and glycosylphosphatidylinositol (GPI)-anchor synthesis. DPMS generates DPM, the substrate for mentioned processes, by the transfer of mannosyl residue from GDP-Man to dolichol phosphate. Here we describe the role of DPMS for Candida albicans physiology with emphasis on the cell wall composition and morphogenesis.
  
  
  METHODS
  C. albicans genes for DPMS subunits were cloned, tagged and expressed in Saccharomyces cerevisiae. The C. albicans strains with controlled expression of DPM genes were constructed and analyzed. Gene expression and enzyme activities were measured using RT-PCR and radioactive substrate. Sensitivities against chemical agents were tested with microdilution method. The composition of the cell wall was estimated by HPLC. Glycosylation status of the marker protein was analyzed by Western blot. Morphological differentiation of the strains was checked on the media promoting hyphae and chlamydospore formation.
  
  
  RESULTS
  We demonstrate that C. albicans DPMS consists of three interacting subunits, among which Dpm1 and Dpm3 are indispensable, whereas Dpm2 increases enzymatic activity. Lowered expression of DPMS genes results in decreased DPMS activity, increased susceptibility to cell wall perturbing agents and in altered cell wall composition. Mutants Tetp-DPM1 and Tetp-DPM3 show defective protein glycosylation and are impaired in hyphae and chlamydospore formation.
  
  
  CONCLUSIONS
  DPMS from C. albicans, opposite to S. cerevisiae, belongs to the family of DPMS with multimeric protein structure.
  
  
  CONCLUSIONS
  This work provides important data about factors required for a proper protein glycosylation and for morphogenesis of pathogenic yeast C. albicans.
authors: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, ul. Pawińskiego 5a, 02-106 Warsaw, Poland. Electronic address: mjuchimiuk@ibb.waw.pl.
authors: Mateusz
authors: M
authors: Juchimiuk
authors: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, ul. Pawińskiego 5a, 02-106 Warsaw, Poland.
authors: Joanna
authors: J
authors: Kruszewska
authors: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, ul. Pawińskiego 5a, 02-106 Warsaw, Poland.
authors: Grażyna
authors: G
authors: Palamarczyk
mesh_terms: D000595:Amino Acid Sequence; D002176:Candida albicans / Q000201:enzymology*; D002473:Cell Wall / Q000737:chemistry; D006031:Glycosylation; D008364:Mannosyltransferases / Q000737:chemistry* / Q000235:genetics; D008969:Molecular Sequence Data
chemical_list: D008364:Mannosyltransferases; C022755:dolichyl-phosphate beta-D-mannosyltransferase
keywords: Candida albicans; Cell wall; Dolichol phosphate mannose synthase; Glycosylation