The Schizosaccharomyces pombe PPR protein Ppr10 associates with a novel protein Mpa1 and acts as a mitochondrial translational activator.
The pentatricopeptide repeat (PPR) proteins characterized by tandem repeats of a degenerate 35-amino-acid motif function in all aspects of organellar RNA metabolism, many of which are essential for organellar gene expression. In this study, we report the characterization of a fission yeast Schizosaccharomyces pombe PPR protein, Ppr10 and a novel Ppr10-associated protein, designated Mpa1. The ppr10 deletion mutant exhibits growth defects in respiratory media, and is dramatically impaired for viability during the late-stationary phase. Deletion of ppr10 affects the accumulation of specific mitochondrial mRNAs. Furthermore, deletion of ppr10 severely impairs mitochondrial protein synthesis, suggesting that Ppr10 plays a general role in mitochondrial protein synthesis. Ppr10 interacts with Mpa1 in vivo and in vitro and the two proteins colocalize in the mitochondrial matrix. The ppr10 and mpa1 deletion mutants exhibit very similar phenotypes. One of Mpa1's functions is to maintain the normal protein level of Ppr10 protein by protecting it from degradation by the mitochondrial matrix protease Lon1. Our findings suggest that Ppr10 functions as a general mitochondrial translational activator, likely through interaction with mitochondrial mRNAs and mitochondrial translation initiation factor Mti2, and that Ppr10 requires Mpa1 association for stability and function.
Jiangsu Key Laboratory for Microbes and Genomics, School of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China.
Yirong
Y
Wang
Jiangsu Key Laboratory for Microbes and Genomics, School of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China.
Jianhua
J
Yan
Jiangsu Key Laboratory for Microbes and Genomics, School of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China.
Qingzhen
Q
Zhang
Jiangsu Key Laboratory for Microbes and Genomics, School of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China.
Xuting
X
Ma
Jiangsu Key Laboratory for Microbes and Genomics, School of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China.
Juan
J
Zhang
Jiangsu Key Laboratory for Microbes and Genomics, School of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China.
Minghui
M
Su
Jiangsu Key Laboratory for Microbes and Genomics, School of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China.
Xiaojun
X
Wang
Jiangsu Key Laboratory for Microbes and Genomics, School of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China.
Ying
Y
Huang
D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D004272:DNA, Mitochondrial / Q000378:metabolism; D039642:Eukaryotic Initiation Factors / Q000378:metabolism; D008928:Mitochondria / Q000235:genetics* / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010641:Phenotype; D014176:Protein Biosynthesis; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D000077278:RNA, Mitochondrial; D016601:RNA-Binding Proteins; D012568:Schizosaccharomyces / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology
D002352:Carrier Proteins; D004272:DNA, Mitochondrial; D039642:Eukaryotic Initiation Factors; D024101:Mitochondrial Proteins; C000621996:Mpa1 protein, S pombe; C000621995:Ppr10 protein, S pombe; D012333:RNA, Messenger; D000077278:RNA, Mitochondrial; D016601:RNA-Binding Proteins; D029702:Schizosaccharomyces pombe Proteins; D012313:RNA