Mss51 and Ssc1 facilitate translational regulation of cytochrome c oxidase biogenesis.
The intricate biogenesis of multimeric organellar enzymes of dual genetic origin entails several levels of regulation. In Saccharomyces cerevisiae, mitochondrial cytochrome c oxidase (COX) assembly is regulated translationally. Synthesis of subunit 1 (Cox1) is contingent on the availability of its assembly partners, thereby acting as a negative feedback loop that coordinates COX1 mRNA translation with Cox1 utilization during COX assembly. The COX1 mRNA-specific translational activator Mss51 plays a fundamental role in this process. Here, we report that Mss51 successively interacts with the COX1 mRNA translational apparatus, newly synthesized Cox1, and other COX assembly factors during Cox1 maturation/assembly. Notably, the mitochondrial Hsp70 chaperone Ssc1 is shown to be an Mss51 partner throughout its metabolic cycle. We conclude that Ssc1, by interacting with Mss51 and Mss51-containing complexes, plays a critical role in Cox1 biogenesis, COX assembly, and the translational regulation of these processes.
Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
Flavia
F
Fontanesi
Iliana C
IC
Soto
Darryl
D
Horn
Antoni
A
Barrientos
D000252:Calcium-Transporting ATPases / Q000502:physiology*; D003576:Electron Transport Complex IV / Q000096:biosynthesis* / Q000235:genetics; D018832:Molecular Chaperones / Q000502:physiology*; D008970:Molecular Weight; D009154:Mutation; D014176:Protein Biosynthesis; D025941:Protein Interaction Mapping; D021122:Protein Subunits / Q000096:biosynthesis / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology*; D014157:Transcription Factors / Q000502:physiology*
D018832:Molecular Chaperones; C519191:Mss51 protein, S cerevisiae; D021122:Protein Subunits; C101767:SSC1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D003576:Electron Transport Complex IV; D000252:Calcium-Transporting ATPases