Rhb1 regulates the expression of secreted aspartic protease 2 through the TOR signaling pathway in Candida albicans

Eukaryot Cell. 2012 Feb;11(2):168-82. doi: 10.1128/EC.05200-11. Epub 2011 Dec 22.

Abstract

Candida albicans is a major fungal pathogen in humans. In C. albicans, secreted aspartyl protease 2 (Sap2) is the most highly expressed secreted aspartic protease in vitro and is a virulence factor. Recent research links the small GTPase Rhb1 to C. albicans target of rapamycin (TOR) signaling in response to nitrogen availability. The results of this study show that Rhb1 is related to cell growth through the control of SAP2 expression when protein is the major nitrogen source. This process involves various components of the TOR signaling pathway, including Tor1 kinase and its downstream effectors. TOR signaling not only controls SAP2 transcription but also affects Sap2 protein levels, possibly through general amino acid control. DNA microarray analysis identifies other target genes downstream of Rhb1 in addition to SAP2. These findings provide new insight into nutrients, Rhb1-TOR signaling, and expression of C. albicans virulence factor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aspartic Acid Endopeptidases / genetics
  • Aspartic Acid Endopeptidases / metabolism*
  • Candida albicans / enzymology*
  • Candida albicans / genetics
  • Candida albicans / metabolism
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism*
  • GTP Phosphohydrolases / metabolism*
  • Gene Expression Regulation, Fungal*
  • Mutation
  • Oligonucleotide Array Sequence Analysis
  • Protein Kinases / genetics
  • Protein Kinases / metabolism*
  • Signal Transduction
  • Virulence / genetics

Substances

  • Fungal Proteins
  • Protein Kinases
  • Aspartic Acid Endopeptidases
  • SAP2 protein, Candida
  • GTP Phosphohydrolases