TY - JOUR
T1 - Mutational analysis of Candida albicans SNF7 reveals genetically separable Rim101 and ESCRT functions and demonstrates divergence in bro1-domain protein interactions
AU - Wolf, Julie M.
AU - Davis, Dana A.
PY - 2010/3
Y1 - 2010/3
N2 - The opportunistic pathogen Candida albicans can grow over a wide pH range, which is associated with its ability to colonize and infect distinct host niches. C. albicans growth in neutral-alkaline environments requires proteolytic activation of the transcription factor Rim101. Rim101 activation requires Snf7, a member of the endosomal sorting complex required for transport (ESCRT) pathway. We hypothesized that Snf7 has distinct functions in the Rim101 and ESCRT pathways, which we tested by alanine-scanning mutagenesis. While some snf7 alleles conferred no defects, we identified alleles with solely ESCRT-dependent, solely Rim101-dependent, or both Rim101- and ESCRT-dependent defects. Thus, Snf7 function in these two pathways is at least partially separable. Both Rim101- and ESCRT-dependent functions require Snf7 recruitment to the endosomal membrane and alleles that disrupted both pathways were found to localize normally, suggesting a downstream defect. Most alleles that conferred solely Rim101-dependent defects were still able to process Rim101 normally under steady-state conditions. However, these same strains did display a kinetic defect in Rim101 processing. Several alleles with solely Rim101-dependent defects mapped to the C-terminal end of Snf7. Further analyses suggested that these mutations disrupted interactions with bro-domain proteins, Rim20 and Bro1, in overlapping but slightly divergent Snf7 domains.
AB - The opportunistic pathogen Candida albicans can grow over a wide pH range, which is associated with its ability to colonize and infect distinct host niches. C. albicans growth in neutral-alkaline environments requires proteolytic activation of the transcription factor Rim101. Rim101 activation requires Snf7, a member of the endosomal sorting complex required for transport (ESCRT) pathway. We hypothesized that Snf7 has distinct functions in the Rim101 and ESCRT pathways, which we tested by alanine-scanning mutagenesis. While some snf7 alleles conferred no defects, we identified alleles with solely ESCRT-dependent, solely Rim101-dependent, or both Rim101- and ESCRT-dependent defects. Thus, Snf7 function in these two pathways is at least partially separable. Both Rim101- and ESCRT-dependent functions require Snf7 recruitment to the endosomal membrane and alleles that disrupted both pathways were found to localize normally, suggesting a downstream defect. Most alleles that conferred solely Rim101-dependent defects were still able to process Rim101 normally under steady-state conditions. However, these same strains did display a kinetic defect in Rim101 processing. Several alleles with solely Rim101-dependent defects mapped to the C-terminal end of Snf7. Further analyses suggested that these mutations disrupted interactions with bro-domain proteins, Rim20 and Bro1, in overlapping but slightly divergent Snf7 domains.
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U2 - 10.1534/genetics.109.112029
DO - 10.1534/genetics.109.112029
M3 - Article
C2 - 20026677
AN - SCOPUS:77950609982
SN - 0016-6731
VL - 184
SP - 673
EP - 694
JO - Genetics
JF - Genetics
IS - 3
ER -