The catalytic subunit of the first mannosyltransferase in the GPI biosynthetic pathway affects growth, cell wall integrity, and hyphal morphogenesis in Candida albicans

Abstract CaGpi14 is the catalytic subunit of the first mannosyltransferase that is involved in the GPI biosynthetic pathway in Candida albicans. We show that CaGPI14 is able to rescue a conditionally lethal gpi14 mutant of S. cerevisiae unlike its mammalian homolog. The depletion of this enzyme in C. albicans leads to severe growth defects, besides causing deficiencies in GPI anchor levels. In addition, CaGpi14 depletion results in cell wall defects and upregulation of the cell wall integrity response pathway. This in turn appears to trigger the osmotic stress dependent activation of the HOG1 pathway and an upregulation of HOG1as well as its downstream target, SKO1, a known suppressor of expression of hyphae specific genes. Consistent with this, mutants of CaGPI14 are unable to undergo hyphal transformations in different hyphae inducing medium, under conditions that produce abundant hyphae in the wild type cells. Hyphal defects in the CaGPI14 mutants could not be attributed either to reduced PKC activation or to defective Ras signaling in these cells but appeared to be driven by perturbations in the HOG1 pathway.
Source: Yeast - Category: Molecular Biology Authors: Tags: ISSY32 Special Issue Source Type: research