title: The PKC, HOG and Ca2+ signalling pathways co-ordinately regulate chitin synthesis in Candida albicans.
abstract: Chitin is an essential component of the fungal cell wall and its synthesis is under tight spatial and temporal regulation. The fungal human pathogen Candida albicans has a four member chitin synthase gene family comprising of CHS1 (class II), CHS2 (class I), CHS3 (class IV) and CHS8 (class I). LacZ reporters were fused to each CHS promoter to examine the transcriptional regulation of chitin synthesis. Each CHS promoter had a unique regulatory profile and responded to the addition of cell wall damaging agents, to mutations in specific CHS genes and exogenous Ca2+. The regulation of both CHS gene expression and chitin synthesis was co-ordinated by the PKC, HOG MAP kinase and Ca2+/calcineurin signalling pathways. Activation of these pathways also resulted in increased chitin synthase activity in vitro and elevated cell wall chitin content. Combinations of treatments that activated multiple pathways resulted in synergistic increases in CHS expression and in cell wall chitin content. Therefore, at least three pathways co-ordinately regulate chitin synthesis and activation of chitin synthesis operates at both transcriptional and post-transcriptional levels.
authors.affiliation: School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK. munro@abdn.ac.uk
authors.forename: Carol A
authors.initials: CA
authors.lastname: Munro
authors.forename: Serena
authors.initials: S
authors.lastname: Selvaggini
authors.forename: Irene
authors.initials: I
authors.lastname: de Bruijn
authors.forename: Louise
authors.initials: L
authors.lastname: Walker
authors.forename: Megan D
authors.initials: MD
authors.lastname: Lenardon
authors.forename: Bertus
authors.initials: B
authors.lastname: Gerssen
authors.forename: Sarah
authors.initials: S
authors.lastname: Milne
authors.forename: Alistair J P
authors.initials: AJ
authors.lastname: Brown
authors.forename: Neil A R
authors.initials: NA
authors.lastname: Gow
mesh_terms: D019677:Artificial Gene Fusion; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D020013:Calcium Signaling; D002176:Candida albicans / Q000235:genetics / Q000378:metabolism*; D002473:Cell Wall / Q000737:chemistry; D002686:Chitin / Q000096:biosynthesis*; D002687:Chitin Synthase / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D017930:Genes, Reporter; D005990:Glycerol / Q000494:pharmacology; D009994:Osmolar Concentration; D011493:Protein Kinase C / Q000378:metabolism*; D015398:Signal Transduction; D001616:beta-Galactosidase / Q000032:analysis / Q000235:genetics
chemical_list: D002686:Chitin; D002687:Chitin Synthase; D011493:Protein Kinase C; D001616:beta-Galactosidase; D005990:Glycerol; D002118:Calcium