A mitochondrial CO2‐adenylyl cyclase‐cAMP signalosome controls yeast normoxic cytochrome c oxidase activity. Issue 10 (1st July 2014)

• Record Type: Journal Article
• Authors: Hess, Kenneth C.; Liu, Jingjing; Manfredi, Giovanni; Mühlschlegel, Fritz A.; Buck, Jochen; Levin, Lonny R.; Barrientos, Antoni
• Is Part Of: FASEB journal. Volume 28:Issue 10(2014)
• Page Start: 4369
• Page End: 4380
• Publication Date: 2014-07-01
• Subjects: Cyr1 -- mitochondrial energy metabolism -- normoxic Cox5a -- hypoxic Cox5b; Biology -- Periodicals; Biology, Experimental -- Periodicals; 570
• DOI: 10.1096/fj.14-252890
• Languages: English
• ISSNs: 0892-6638

Abstract

Abstract : Mitochondria, the major source of cellular energy in the form of ATP, respond to changes in substrate availability and bioenergetic demands by employing rapid, short‐term, metabolic adaptation mechanisms, such as phosphorylation‐dependent protein regulation. In mammalian cells, an intramitochondrial CO2 ‐adenylyl cyclase (AC)‐cyclic AMP (cAMP)‐protein kinase A (PKA) pathway regulates aerobic energy production. One target of this pathway involves phosphorylation of cytochrome c oxidase (COX) subunit 4‐isoform 1 (COX4i1), which modulates COX allosteric regulation by ATP. However, the role of the CO2 ‐sAC‐cAMP‐PKA signalosome in regulating COX activity and mitochondrial metabolism and its evolutionary conservation remain to be fully established. We show that in Saccharomyces cerevisiae, normoxic COX activity measured in the presence of ATP is 55% lower than in the presence of ADP. Moreover, the adenylyl cyclase Cyr1 activity is present in mitochondria, and it contributes to the ATP‐mediated regulation of COX through the normoxic subunit Cox5a, homologue of human COX4i1, in a bicarbonate‐sensitive manner. Furthermore, we have identified 2 phosphorylation targets in Cox5a (T65 and S43) that modulate its allosteric regulation by ATP. These residues are not conserved in the Cox5b‐containing hypoxic enzyme, which is not regulated by ATP. We conclude that across evolution, a CO2 ‐sAC‐cAMP‐PKA axis regulates normoxic COX activity.—Hess, K. C., Liu, J., Manfredi, G., Mühlschlegel, F. A., Buck, J., Levin, L. R., Barrientos, A., A mitochondrial CO2‐adenylyl cyclase‐cAMP signalosome controls yeast normoxic cytochrome c oxidase activity. FASEB J. 28, 4369–4380 (2014). www.fasebj.org