title: Utilization of the mating scaffold protein in the evolution of a new signal transduction pathway for biofilm development.
abstract: Among the hemiascomycetes, only Candida albicans must switch from the white phenotype to the opaque phenotype to mate. In the recent evolution of this transition, mating-incompetent white cells acquired a unique response to mating pheromone, resulting in the formation of a white cell biofilm that facilitates mating. All of the upstream components of the white cell response pathway so far analyzed have been shown to be derived from the ancestral pathway involved in mating, except for the mitogen-activated protein (MAP) kinase scaffold protein, which had not been identified. Here, through binding and mutational studies, it is demonstrated that in both the opaque and the white cell pheromone responses, Cst5 is the scaffold protein, supporting the evolutionary scenario proposed. Although Cst5 plays the same role in tethering the MAP kinases as Ste5 does in Saccharomyces cerevisiae, Cst5 is approximately one-third the size and has only one rather than four phosphorylation sites involved in activation and cytoplasmic relocalization.
authors.affiliation: The Developmental Studies Hybridoma Bank-Microbe, Department of Biology, the University of Iowa, Iowa City, Iowa, USA.
authors.forename: Song
authors.initials: S
authors.lastname: Yi
authors.forename: Nidhi
authors.initials: N
authors.lastname: Sahni
authors.forename: Karla J
authors.initials: KJ
authors.lastname: Daniels
authors.forename: Kevin L
authors.initials: KL
authors.lastname: Lu
authors.forename: Guanghua
authors.initials: G
authors.lastname: Huang
authors.forename: Adam M
authors.initials: AM
authors.lastname: Garnaas
authors.forename: Claude
authors.initials: C
authors.lastname: Pujol
authors.forename: Thyagarajan
authors.initials: T
authors.lastname: Srikantha
authors.forename: David R
authors.initials: DR
authors.lastname: Soll
mesh_terms: D018441:Biofilms / Q000254:growth & development*; D005075:Biological Evolution; D002176:Candida albicans / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D049770:Genes, Mating Type, Fungal; D034521:Nuclear Matrix-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D010675:Pheromones / Q000378:metabolism; D011485:Protein Binding; D015398:Signal Transduction
chemical_list: D005656:Fungal Proteins; D034521:Nuclear Matrix-Associated Proteins; D010675:Pheromones