Coa2 Is an Assembly Factor for Yeast Cytochrome c Oxidase Biogenesis That Facilitates the Maturation of Cox1

Authors

Fabien Pierrel, University of Utah Health Sciences Center
Oleh Khalimonchuk, University of Nebraska-LincolnFollow
Paul A. Cobine, University of Utah Health Sciences Center
Megan Bestwick, University of Utah Health Sciences Center
Dennis R. Winge, University of Utah Health Sciences Center

Date of this Version

2008

Citation

MOLECULAR AND CELLULAR BIOLOGY, Aug. 2008, p. 4927–4939 Vol. 28, No. 16

Comments

Copyright © 2008, American Society for Microbiology. All Rights Reserved.

Abstract

The assembly of cytochrome c oxidase (CcO) in yeast mitochondria is dependent on a new assembly factor designated Coa2. Coa2 was identified from its ability to suppress the respiratory deficiency of coa1 Δ and shy1 Δ cells. Coa1 and Shy1 function at an early step in maturation of the Cox1 subunit of CcO. Coa2 functions downstream of the Mss51-Coa1 step in Cox1 maturation and likely concurrent with the Shy1-related heme a₃ insertion into Cox1. Coa2 interacts with Shy1. Cells lacking Coa2 show a rapid degradation of newly synthesized Cox1. Rapid Cox1 proteolysis also occurs in shy1 Δ cells, suggesting that in the absence of Coa2 or Shy1, Cox1 forms an unstable conformer. Overexpression of Cox10 or Cox5a and Cox6 or attenuation of the proteolytic activity of the m-AAA protease partially restores respiration in coa2 Δ cells. The matrix-localized Coa2 protein may aid in stabilizing an early Cox1 intermediate containing the nuclear subunits Cox5a and Cox6.