The Ady2 “NPAPLGL(M/S)” motif is critical for acetate uptake and binding

Abstract

Organic acids, such as acetate, are recognized as one of the most prevalent compounds in ecosystems and the transport, biosynthesis, and assimilation of these molecules represent an adaptive advantage for organisms. The majority of AceTr family members so far characterized were associated with the active transport of acetate. AceTr proteins have six predicted transmembrane segments (TMS), sharing the conserved motif NPAPLGL(M/S) located at the beginning of the first TMS. Gpr1 from Yarrowia lipolytica was the first AceTr family member identified in yeasts, being involved in acetic acid sensitivity, cell and colony morphology, yeast-to-hyphae transition and cell lifespan. The Saccharomyces cerevisiae has 3 homologous genes, ADY2, FUN34 and ATO3 was latter characterized as an acetate proton symporter. In this work, we identified the residues of the conserved motif NPAPLGL(M/S) as essential for substrate uptake and binding, but not for membrane targeting. Furthermore, we demonstrated that the Gpr1 from Y. lipolytica is an acetate permease and the S. cerevisiae Fun34 does not transport acetate. Phylogenetic analysis of AceTr family shows that it is dispersed in the tree of life. In eukaryotes, however, it is almost limited to microbes, though reaching a prevalence close to 100% in fungi, where it may play an essential role in fungal survival.