Mitochondrial cytochrome c oxidase subunit IV is phosphorylated by an endogenous kinase

Abstract

This study was undertaken to identify novel mitochondrial membrane proteins that are potential targets for phosphorylation. Mitochondrial membranes were incubated in the presence of [y-32 P!ATP and the Triton X-114 extractable protein was subjected to ion-exchange and polyacrylamide gel chromatography to purify a major phosphorylated protein of approximately 17000 Da. The determined peptide sequence of the purified phosphoprotein corresponded to a segment of cytochrome c oxidase subunit IV, an inner membrane protein of 17160 Da. The identity of the phosphoprotein was confirmed by two-dimensional electrophoresis and Western blotting. The results identify mitochondrial cytochrome c oxidase subunit IV as a protein which is phosphorylated by an endogenous kinase.

β1-Adrenoreceptor activation contributes to ischemia-reperfusion damage as well as playing a role in ischemic preconditioning

“…The CcO activity is substantially altered in mammalian cells exposed to acute hypoxia and tissues subjected to ischemia-reperfusion (10,11,24,25,40). We (40) and others (5,28,47) have previously shown that cAMP-mediated phosphorylation plays a role in the regulation of CcO activity. In a previous study (40) we subjected our Langendorff-perfused rabbit hearts to varying degrees of global and regional ischemia.…”

Dual effects of sodium tungstate on adipocyte biology: inhibition of adipogenesis and stimulation of cellular oxygen consumption

“…Increasing reports over the past few years suggest a direct regulation of mitochondrial activity by phosphorylation events in several cell types, in which some classical cytosolic kinases are found in mitochondria [32][33][34][35] acting on different subunits of the respiratory chain complexes. [36][37][38][39][40][41] We cannot exclude a direct regulation of mitochondrial activity by sodium tungstate. If this is the case, sodium tungstate would open up a new Dual effects of tungstate on adipocyte biology MC Carmona et al…”

Additive Effects of Mitochondrion-targeted Cytochrome CYP2E1 and Alcohol Toxicity on Cytochrome c Oxidase Function and Stability of Respirosome Complexes

“…In hypoxia and myocardial ischemia conditions, mitochondrial dysfunction was shown to be associated with loss of CcO activity (28,31,81), which was associated with selective loss of mitochondrion-encoded subunit I that houses the heme a/a3 and copper centers, and nuclear gene-coded subunits IVI1 and Vb (82)(83)(84). Protein phosphorylation was implicated in these losses (28,31,(85)(86)(87). Interestingly, our results show the loss of the same two nucleus-encoded subunits (IVI1 and Vb) in alcohol-treated Mt ϩϩ cells and also in livers of rats fed with alcohol for Ͻ6 weeks (Fig.…”