The ATC1 Gene Encodes a Cell Wall-linked Acid Trehalase Required for Growth on Trehalose in Candida albicans

Abstract

After screening a Candida albicans genome data base, the product of an open reading frame (IPF 19760/ CA2574) with 41% identity to Saccharomyces cerevisiae vacuolar acid trehalase (Ath1p) was identified and named Atc1p. The deduced amino acid sequence shows that Atc1p contains an N-terminal hydrophobic signal peptide and 20 potential sites for N-glycosylation. C. albicans homozygous mutants that lack acid trehalase activity were constructed by gene disruption at the two ATC chromosomal alleles. Analysis of these null mutants shows that Atc1p is localized in the cell wall and is required for growth on trehalose as a carbon source. An Atc1p endowed with acid trehalase activity was obtained by an in vtro transcription-translation coupled system. These results strongly suggest that ATC1 is the structural gene encoding cell wall acid trehalase in C. albicans. Determinations of ATC1 mRNA expression as well as acid trehalase activity in the presence and absence of glucose point out that ATC1 gene is regulated by glucose repression.

Pga13 in Candida albicans is localized in the cell wall and influences cell surface properties, morphogenesis and virulence

“…S1. Genomic DNA and RNA isolation and blotting was performed as described (Castillo et al, 2006;Pedreño et al, 2004). Northern blot verification was conducted with a probe spanning PGA13 region +233 to +1001 (not shown).…”

“…For pattern scanning and obtaining the serine/threonine composition scanning plot we used ProFASTA (http://www.bioinformatics.nl/tools/profasta/; De Groot and Brandt, 2012 Table S1. C. albicans transformations were performed as described (Pedreño et al, 2004). As URA3 expression levels may influence phenotypes of C. albicans mutants, URA3 expression was restored in the ura3 genetic backgrounds (including the CAI4 parental strain) by expressing URA3 in the neutral RPS1 locus using the CIp10 plasmid (Moreno et al, 2010;Murad et al, 2000).…”

Candida albicansCell Wall Proteins

“…Trehalose is a nonreducing disaccharide. Atc1p, acid trehalase, which contains a possible signal sequence for classical secretion, is one of two enzymes hydrolyzing trehalose (290). This enzyme has been recovered from isolated cell walls.…”

The Saccharomyces cerevisiae vacuolar acid trehalase is targeted at the cell surface for its physiological function

“…Although fungal acid trehalases, including those of the yeast Candida albicans [9] and Kluyveromyces lactis [10], have been reported to be localized at the cell surface, the localization of the S. cerevisiae acid trehalase remains a matter of controversy. In 1982, Wiemken and co-workers [11] first identified this protein in a vacuole-enriched fraction obtained by density gradient Previous studies in the yeast Saccharomyces cerevisiae have proposed a vacuolar localization for Ath1, which is difficult to reconcile with its ability to hydrolyze exogenous trehalose.…”

“…Invertase is a secreted protein with a classical signal peptide at its N-terminus (amino acids [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] for secretion at the cell periphery.…”