Coenzyme Q supplementation or Over-Expression of the Yeast Coq8 Putative Kinase Stabilizes Multi-Subunit Coq Polypeptide Complexes in Yeast Coq Null Mutants

Identification of Coq11, a New Coenzyme Q Biosynthetic Protein in the CoQ-Synthome in Saccharomyces cerevisiae

“…In addition Coq8 was observed to co-purify with a Coq6-containing complex, but not with tagged Coq3 or Coq9, suggesting a closer association with Coq6. Although Coq8 is required for the stability of the Coq polypeptides and the biosynthetic complex (20,28), this is the first evidence showing direct association of Coq8 with the complex.…”

“…For example, the late stage Q intermediate DMQ 6 co-purifies with the Q biosynthetic complex (25), and exogenous Q 6 has been shown to stabilize particular Coq proteins and lead to production of later stage biosynthetic intermediates in certain coq mutants (27)(28)(29), suggesting a function for Q or a Q intermediate in the stability of the CoQ-synthome. Coq4 was previously hypothesized to serve as a scaffolding protein for the complex, and the crystal structure of the Coq4 homolog Alr8543 from Nostoc sp.…”

“…Co-precipitation experiments have demonstrated the physical association of several of the Coq proteins; biotinylated Coq3 was shown to co-precipitate Coq4 and HA-tagged Coq9 co-purified Coq4, Coq5, Coq6, and Coq7 (21,25). Although Coq8 has not been shown to be associated in a complex with the other Coq proteins, its putative role as a kinase is important for the stability of several other Coq proteins because overexpression of COQ8 in various coq⌬ mutants stabilizes several of the other Coq proteins, as well as multisubunit Coq polypeptide complexes, and leads to the accumulation of later stage Q biosynthetic intermediates diagnostic of the mutated step (20,28,29).…”

“…Analysis of gel filtration fractions has also shown the association of demethoxy-Q 6 (DMQ 6 ) with the complexes (25). Supplementation of exogenous Q 6 was shown to stabilize the steady-state levels of Coq3 and Coq4 in the coq7⌬ mutant (27), enhance DMQ 6 production in the coq7⌬ mutant (29), and stabilize steady-state levels of Coq9 in the coq3⌬, coq4⌬, coq6⌬, coq7⌬ mutants and steady-state levels of Coq4 in the coq3⌬, coq6⌬, and coq7⌬ mutants (28), suggesting that associated Q 6 plays a role in the stability of the complex.…”

RNA-binding proteins regulate cell respiration and coenzyme Q biosynthesis by post-transcriptional regulation ofCOQ7

“…[16][17][18] Additionally, recent literature highlights the importance of the post-transcriptional control of COQ proteins and the structure of the complex in the regulation of CoQ 10 levels. 40 Specifically, COQ7 is regulated by phosphorylation depending on nutritional conditions and is regulated in part by the PTC7 mitochondrial phosphatase. 19,20 COQ7 protein also requires COQ9 encoded peptide interaction for its activity.…”