title: Hyphal growth in Candida albicans requires the phosphorylation of Sec2 by the Cdc28-Ccn1/Hgc1 kinase.
abstract: Polarized growth is a fundamental property of cell growth and development. It requires the delivery of post-Golgi secretory vesicles to the site of polarized growth. This process is mediated by Rab GTPases activated by their guanine exchange factors (GEFs). The human fungal pathogen, Candida albicans, can grow in a budded yeast form or in a highly polarized hyphal form, and thus provides a model to study this phenomenon. During hyphal, but not yeast growth, secretory vesicles accumulate in an apical body called a Spitzenkörper, which acts to focus delivery of the vesicles to the tip. Post-Golgi transport of secretory vesicles is mediated by the Rab GTPase Sec4, activated by its GEF Sec2. Using a combination of deletion mapping, in vitro mutagenesis, an analogue-sensitive allele of Cdc28 and an in vitro kinase assay, we show that localization of Sec2 to the Spitzenkörper and normal hyphal development requires phosphorylation of Serine 584 by the cyclin-dependent kinase Cdc28. Thus, as well as controlling passage through the cell cycle, Cdc28 has an important function in controlling polarized secretion.
authors.affiliation: Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield, UK.
authors.forename: Amy
authors.initials: A
authors.lastname: Bishop
authors.forename: Rachel
authors.initials: R
authors.lastname: Lane
authors.forename: Richard
authors.initials: R
authors.lastname: Beniston
authors.forename: Bernardo
authors.initials: B
authors.lastname: Chapa-y-Lazo
authors.forename: Carl
authors.initials: C
authors.lastname: Smythe
authors.forename: Peter
authors.initials: P
authors.lastname: Sudbery
mesh_terms: D015153:Blotting, Western; D042846:CDC2-CDC28 Kinases / Q000378:metabolism*; D002176:Candida albicans / Q000737:chemistry / Q000254:growth & development*; D055515:Cysteine-Rich Protein 61 / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006801:Humans; D025301:Hyphae / Q000737:chemistry / Q000254:growth & development*; D008853:Microscopy; D008856:Microscopy, Fluorescence; D016296:Mutagenesis; D010766:Phosphorylation; D017384:Sequence Deletion
chemical_list: D055515:Cysteine-Rich Protein 61; D005656:Fungal Proteins; D042846:CDC2-CDC28 Kinases; D019204:GTP-Binding Proteins