Signal Transduction Pathways Regulating Switching, Mating and Biofilm Formation in Candida albicans and Related Species

Abstract

The developmental programs of Candida albicans are complex and intertwined. They include hypha formation, white-opaque switching, mating and biofilm formation. Here, the regulation of the latter three programs are considered. White-opaque switching is repressed by the a1-α2 corepressors complex produced in a/α but not a/a or α/α cells, and regulated in the latter by WOR1, a master regulator of switching. Mating of opaque cells is regulated by pheromone induction of a MAP kinase pathway targeting the transcription factor Cph1. Biofilm formation by a/a and α/α cells is regulated by the same pheromone-induced MAP kinase pathway, but targets a different transcription factor, Tec1. And biofilm formation by a/α cells is regulated by the Ras1/cAMP pathway, the same pathway regulating hypha formation, but targets an additional transcription factor, Bcr1. Specific overlaps suggest quite interesting scenarios for the evolution of these pathways, most notably that for a/a and α/α biofilm formation.