A hunt for OM45 synthetic petite interactions in Saccharomyces cerevisiae reveals a role for Miro GTPase Gem1p in cristae structure maintenance

A screen for mutations inSaccharomyces cerevisiae that are synthetically respiratory deficient with a deletion of theOM45 gene (encoding a major yeast mitochondrial outer membrane protein), led to the isolation of mutations inUGO1 andGEM1. Our results indicate the inner mitochondrial membrane (IMM) as the location of action of Om45 and the Miro GTPase Gem1, and a role for these proteins in the maintenance of IMM morphology and mitochondrial DNA. (A) WT state; (B) TheΔom45 strain has no detectable phenotype; (C) TheΔom45Δgem1 synthetic petite (SPM) strain is respiratory deficient, displays severely disturbed IMM morphology and loss of mitochondrial DNA. AbstractOm45 is a major protein of the yeast's outer mitochondrial membrane under respiratory conditions. However, the cellular role of the protein has remained obscure. Previously, deletion mutant phenotypes have not been found, and clear amino acid sequence similarities that would allow inferring its functional role are not available. In this work, we describe synthetic petite mutants ofGEM1 andUGO1 that depend on the presence ofOM45 for respiratory growth, as well as the identification of several multicopy suppressors of the synthetic petite phenotypes. In the analysis of our mutants, we demonstrate that Om45p and Gem1p have a collaborative role in the maintenance of mitochondrial morphology, cristae structure, and mitochondrial DNA maintenance. A group of multicopy suppressors rescuing the synthetic lethal phenotypes of ...
Source: MicrobiologyOpen - Category: Microbiology Authors: Tags: ORIGINAL ARTICLE Source Type: research