A Haloacid Dehalogenase of Candida albicans: An uncharted territory

Abstract

Candida albicans resides in human body as commensal and can turn pathogenic when immune defences are perturbed. One of the important fitness attributes in the host-niche includes robust stress-responses to local environmental insults. This adaptive response is regulated, at least in part, by osmosensing signaling system called the HOG1 (High Osmolarity Glycerol) MAPK pathway. The detailed molecular mechanism involved in Hog1 mediated responses are poorly understood although several target genes are reported. In the present study we have characterized a Hog1 induced Haloacid dehalogenase family protein (Had1), and shown it to be a phosphoprotein phosphatase. We have investigated the PostTranslationalModifications (PTMs) and interacting proteins of this novel phosphatase by employing TAP tag strategy, LC-MS/MS and CO-IP analysis. Our studies reveal that a specific Phophorylation pattern of this protein modulates its localization dynamics and activity. Had1 interacts with Erg13 (HMG Co-A synthase), a component involved in mitochondrial membrane lipid biosynthesis pathway, probably to maintain the functional integrity of membranes. A novel regulatory loop involved in salt tolerance is mediated by Had1. In such a regulation, different signalling pathways like HOG1 osmotic pathway and the glucose repression pathway use distinct promoter elements of HAD1 via specific transcriptional repressors like Sko1p and Mig1p. Taken together, our work contributes towards gaining a functional insight into a class of phosphatases that probably has evolved with novel specificities in the pathogenic yeast Candida albicans. Support or Funding Information DST-SERB (Dept. of Science and Technology-Science and Engineering Research Board), Govt. of India, India A) Western blot representing the expression of Had1.GFP in response to salt and peroxide at 3Hrs induction. B)Western blot showing the phosphorylated band of CaHad1.GFP for KCl induced cells on low percentage SDS-PAGE gel. (PPase- alkaline phosphatase. PPi-Phophatase inhibitor. C)phosphorylation sites identified by LC-MS/MS analysis on endogenous CaHad, purified by TAP tag strategy This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.