Can Yeast Salvage Folate? Bioinformatics Suggests Yes!

Folate is an important nutrient for cell growth and division in all organisms. Many microorganisms including prokaryotes and eukaryotes can synthesize their own folate while humans cannot. To assimilate folate into the cell a folate transporter is required for uptake through the cell membrane. Three types of folate transporters are known to exist in humans to facilitate the uptake of folate: Reduced Folate Carrier (RFC), Proton-Coupled Folate Transporter (PCFT) and Folate Receptors (FR). Although yeast cells can synthesize their own folate, laboratory evidence suggests that it can also utilize folate from exogenous source. However, little is known about the presence of folate transporters and other proteins involved in utilization of folate in yeasts. Hence using various bioinformatics analysis tools we attempted to determine the types of folate transporter present using genome sequences of well-studied yeasts from Entrez Database, Yeast Genome Database and Candia Genome Databases. Bioinformatics suggests the folate transporter present the yeast is similar to human PCFT with significant identity. All yeast possessed genes to encode the putative proteins which are similar to human PCFT. Saccharomyces cerevisiae’s putative protein had the highest identity match (identity=30.2%, E-value= <0.05) while Candida glabrata had the lowest (identity=22.6%, E-value: <0.05). Phylogenetic analysis showed yeast PCFT being distant from human PCFT but the conserved domain and hydropathy analysis indicated that it performs similar function to the human PCFT. Although bioinformatics suggests the presence of PCFT in yeast, genetic studies in the future could further help to understand the PCFT. If laboratory results are consistent with our finding the yeast could be used as a model organism to study many diseases in humans related to PCFT.