Control of pseudohyphae formation in Saccharomyces cerevisiae

• Published in: FEMS microbiology reviews 2001-01, Vol.25 (1), p.107-123
• Main Author: Gancedo, Juana M.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Candida albicans; Cell adhesion; Cell adhesion & migration; Cell surface; Cyclic AMP; Deprivation; Dimorphism; Diploids; Elongation; FLO11 gene; flocullin; Fundamental and applied biological sciences. Psychology; Fungal Proteins - genetics; Fungal Proteins - metabolism; Gene expression; Gene Expression Regulation, Fungal; Homology; Hyphae; Invasive growth; Kinases; MAP kinase; Microbiology; Mode of action; Morphogenesis; Morphology, structure, chemical composition; MUC1 gene; Mycology; Protein kinase; Protein kinase A; Proteins; Pseudohypha; Pseudohyphae; Saccharomyces cerevisiae; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - growth & development; Signal Transduction; Ste12 protein; Tpk2 protein; Yeast; Yeasts
• ISSN: 0168-6445; 1574-6976; 1574-6976
• DOI: 10.1111/j.1574-6976.2001.tb00573.x

Abstract Pseudohyphal growth in both haploid and diploid strains of Saccharomyces cerevisiae reflects concerted changes in different cellular processes: budding pattern, cell elongation and cell adhesion. These changes are triggered by environmental signals and are controlled by several pathways which act in parallel. Nitrogen deprivation, and possibly other stresses, activate a MAP kinase cascade which has the transcription factor Ste12 as its final target. A cAMP-dependent pathway, in which the protein kinase Tpk2 plays a specific role, is also required for the morphogenetic switch. Both pathways contribute to modulate the expression of the MUC1/FLO11 gene which encodes a cell-surface flocculin required for pseudohyphal and invasive growth. The MAP kinase cascade could also control the activity of the cyclin/Cdc28 complexes which affect both the budding pattern of yeast and cell elongation. A further protein which stimulates filamentous growth in S. cerevisiae is Phd1; although its mode of action is unknown, it may be regulated by a cAMP-dependent protein kinase, as occurs with the homologous protein Efg1 from Candida albicans, which is required for the formation of true hyphae. Morphogenesis in different yeast genera share common elements, but there are also important differences. Although a complete picture cannot yet be drawn, partial models may be proposed for the interaction of the regulatory pathways, both in the case of S. cerevisiae and in that of C. albicans.