A hunt for OM45 synthetic petite interactions in Saccharomyces cerevisiae reveals a role for Miro GTPase Gem1p in cristae structure maintenance. Issue 5 (8th October 2021)

• Record Type: Journal Article
• Authors: Shvetsova, Antonina; Masud, Ali J.; Schneider, Laura; Bergmann, Ulrich; Monteuuis, Geoffray; Miinalainen, Ilkka J.; Hiltunen, J. Kalervo; Kastaniotis, Alexander J.
• Is Part Of: MicrobiologyOpen. Volume 10:Issue 5(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-10-08
• Subjects: cristae organization -- GEM1 -- Miro GTPase -- mitochondria -- mtDNA inheritance -- OM45 -- outer and inner mitochondrial membranes -- UGO1; Microbiology -- Periodicals; 579
• DOI: 10.1002/mbo3.1238
• Languages: English
• ISSNs: 2045-8827

Abstract

Abstract: Om45 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 of GEM1 and UGO1 that depend on the presence of OM45 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 the mutants on non‐fermentable carbon sources additionally supports this result. Our results imply that the synthetic petite phenotypes we observed are due to the disturbance of the inner mitochondrial membrane and point to this mitochondrial sub‐compartment as the main target of action of Om45p, Ugo1p, and the yeast Miro GTPase Gem1p. Abstract : A screen for mutations in Saccharomyces cerevisiae that are synthetically respiratory deficient with a deletion of the OM45 gene (encoding a major yeast mitochondrial outer membrane protein), led to the isolation of mutations in UGO1 and GEM1 . 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) The Δom45 strain has no detectable phenotype; (C) The Δom45Δgem1 synthetic petite (SPM) strain is respiratory deficient, displays severely disturbed IMM morphology and loss of mitochondrial DNA.