Structural and functional study of YER067W, a new protein involved in yeast metabolism control and drug resistance.
The genome of Saccharomyces cerevisiae is arguably the best studied eukaryotic genome, and yet, it contains approximately 1000 genes that are still relatively uncharacterized. As the majority of these ORFs have no homologs with characterized sequence or protein structure, traditional sequence-based approaches cannot be applied to deduce their biological function. Here, we characterize YER067W, a conserved gene of unknown function that is strongly induced in response to many stress conditions and repressed in drug resistant yeast strains. Gene expression patterns of YER067W and its paralog YIL057C suggest an involvement in energy metabolism. We show that yeast lacking YER067W display altered levels of reserve carbohydrates and a growth deficiency in media that requires aerobic metabolism. Impaired mitochondrial function and overall reduction of ergosterol content in the YER067W deleted strain explained the observed 2- and 4-fold increase in resistance to the drugs fluconazole and amphotericin B, respectively. Cell fractionation and immunofluorescence microscopy revealed that Yer067w is associated with cellular membranes despite the absence of a transmembrane domain in the protein. Finally, the 1.7 A resolution crystal structure of Yer067w shows an alpha-beta fold with low similarity to known structures and a putative functional site.YER067W's involvement with aerobic energetic metabolism suggests the assignment of the gene name RGI1, standing for respiratory growth induced 1. Altogether, the results shed light on a previously uncharacterized protein family and provide basis for further studies of its apparent role in energy metabolism control and drug resistance.
Domitrovic
Tatiana
T
Programa de Biologia Molecular e Estrutural, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. domitrovic@biof.ufrj.br
Kozlov
Guennadi
G
Freire
João Claudio Gonçalves
JC
Masuda
Claudio Akio
CA
da Silva Almeida
Marcius
M
Montero-Lomeli
Mónica
M
Atella
Georgia Correa
GC
Matta-Camacho
Edna
E
Gehring
Kalle
K
Kurtenbach
Eleonora
E
D000595:Amino Acid Sequence; D000666:Amphotericin B / Q000494:pharmacology; D000935:Antifungal Agents / Q000494:pharmacology; D002244:Carbon / Q000378:metabolism; D004352:Drug Resistance, Microbial; D004734:Energy Metabolism / Q000235:genetics; D015725:Fluconazole / Q000494:pharmacology; D005800:Genes, Fungal; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D011487:Protein Conformation; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D017386:Sequence Homology, Amino Acid
D000935:Antifungal Agents; D008565:Membrane Proteins; C551793:RGI1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D002244:Carbon; D000666:Amphotericin B; D015725:Fluconazole