RPM2, independently of its mitochondrial RNase P function, suppresses an ISP42 mutant defective in mitochondrial import and is essential for normal growth

C K Kassenbrock; G J Gao; K R Groom; P Sulo; M G Douglas; N C Martin

doi:10.1128/MCB.15.9.4763

RPM2, independently of its mitochondrial RNase P function, suppresses an ISP42 mutant defective in mitochondrial import and is essential for normal growth

Mol Cell Biol. 1995 Sep;15(9):4763-70. doi: 10.1128/MCB.15.9.4763.

Authors

C K Kassenbrock¹, G J Gao, K R Groom, P Sulo, M G Douglas, N C Martin

Affiliation

¹ Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, USA.

Abstract

RPM2 is identified here as a high-copy suppressor of isp42-3, a temperature-sensitive mutant allele of the mitochondrial protein import channel component, Isp42p. RPM2 already has an established role as a protein component of yeast mitochondrial RNase P, a ribonucleoprotein enzyme required for the 5' processing of mitochondrial precursor tRNAs. A relationship between mitochondrial tRNA processing and protein import is not readily apparent, and, indeed, the two functions can be separated. Truncation mutants lacking detectable RNase P activity still suppress the isp42-3 growth defect. Moreover, RPM2 is required for normal fermentative yeast growth, even though mitochondrial RNase P activity is not. The portion of RPM2 required for normal growth and suppression of isp42-3 is the same. We conclude that RPM2 is a multifunctional gene. We find Rpm2p to be a soluble protein of the mitochondrial matrix and discuss models to explain its suppression of isp42-3.

MeSH terms

Amino Acid Sequence
Base Sequence
Biological Transport / genetics
Cell Compartmentation
DNA Mutational Analysis
Endoribonucleases / metabolism
Fungal Proteins / genetics*
Fungal Proteins / metabolism
Gene Dosage
Genes, Fungal / genetics
Genes, Lethal
Membrane Transport Proteins*
Mitochondria / chemistry
Mitochondria / genetics
Mitochondria / metabolism*
Mitochondrial Membrane Transport Proteins
Molecular Sequence Data
Open Reading Frames / genetics
RNA / metabolism
RNA Processing, Post-Transcriptional
RNA, Catalytic / metabolism
RNA, Mitochondrial
RNA, Transfer / metabolism
Ribonuclease P
Saccharomyces cerevisiae / genetics*
Saccharomyces cerevisiae / growth & development
Saccharomyces cerevisiae Proteins*
Sequence Deletion
Structure-Activity Relationship
Suppression, Genetic*

Substances

Fungal Proteins
Membrane Transport Proteins
Mitochondrial Membrane Transport Proteins
RNA, Catalytic
RNA, Mitochondrial
Saccharomyces cerevisiae Proteins
Tom40 protein, S cerevisiae
RNA
RNA, Transfer
Endoribonucleases
Ribonuclease P