TY - JOUR
T1 - CLD1 Reverses the ubiquinone insufficiency of mutant cat5/coq7 in a Saccharomyces cerevisiae model system
AU - Kar, Adwitiya
AU - Beam, Haley
AU - Borror, Megan B.
AU - Luckow, Michael
AU - Gao, Xiaoli
AU - Rea, Shane L.
N1 - Funding Information:
Dr. Rob Poyton (CU Boulder) for help with tetrad dissections. Mass spectrometry analyses were conducted in the Metabolomics Core Facility of the Mass Spectrometry Laboratory at the University of Texas Health Science Center at San Antonio, with instrumentation funded in part by NIH Grant 1S10RR031586-01. Additional financial support was provided by the Ellison Medical Foundation ( http://www.ellisonfoundation.org/ ; AG-NS-051908; S.L.R.), the National Institute on Aging ( https://www.nia.nih.gov/ ; AG-025207, AG-047561; S.L.R.), and the National Institute for General Medical Sciences ( https://www.nigms.nih.gov ,; K12-GM111726; M.B.B.). We thank Dr. Gian Paolo Littarru (Polytechnic University of The Marche, Ancona, Italy) for providing purified Q, Dr. Randy Glickman (UTHSCSA, TX.) for access to HPLC instrumentation, and Oxana Radetskaya for critical comments on the manuscript. Funding sources had no role in study design, data collection or analysis, our decision to publish, or preparation of the manuscript. The authors declare there are no conflicting interests controlling the publication of this manuscript. 6
Publisher Copyright:
© 2016 Kar et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
PY - 2016/9
Y1 - 2016/9
N2 - Ubiquinone (Qn ) functions as a mobile electron carrier in mitochondria. In humans, Q biosynthetic pathway mutations lead to Q10 deficiency, a life threatening disorder. We have used a Saccharomyces cerevisiae model of Q6 deficiency to screen for new modulators of ubiquinone biosynthesis. We generated several hypomorphic alleles of coq7/cat5 (clk-1 in Caenorhabditis elegans) encoding the penultimate enzyme in Q biosynthesis which converts 5-demethoxy Q6 (DMQ6) to 5-demethyl Q6 , and screened for genes that, when overexpressed, suppressed their inability to grow on non-fermentable ethanol-implying recovery of lost mitochondrial function. Through this approach we identified Cardiolipin-specific Deacylase 1 (CLD1), a gene encoding a phospholipase A2 required for cardiolipin acyl remodeling. Interestingly, not all coq7 mutants were suppressed by Cld1p overexpression, and molecular modeling of the mutant Coq7p proteins that were suppressed showed they all contained disruptions in a hydrophobic α-helix that is predicted to mediate membrane-binding. CLD1 overexpression in the suppressible coq7 mutants restored the ratio of DMQ6 to Q6 toward wild type levels, suggesting recovery of lost Coq7p function. Identification of a spontaneous Cld1p loss-of-function mutation illustrated that Cld1p activity was required for coq7 suppression. This observation was further supported by HPLC-ESI-MS/MS profiling of monolysocardiolipin, the product of Cld1p. In summary, our results present a novel example of a lipid remodeling enzyme reversing a mitochondrial ubiquinone insufficiency by facilitating recovery of hypomorphic enzymatic function.
AB - Ubiquinone (Qn ) functions as a mobile electron carrier in mitochondria. In humans, Q biosynthetic pathway mutations lead to Q10 deficiency, a life threatening disorder. We have used a Saccharomyces cerevisiae model of Q6 deficiency to screen for new modulators of ubiquinone biosynthesis. We generated several hypomorphic alleles of coq7/cat5 (clk-1 in Caenorhabditis elegans) encoding the penultimate enzyme in Q biosynthesis which converts 5-demethoxy Q6 (DMQ6) to 5-demethyl Q6 , and screened for genes that, when overexpressed, suppressed their inability to grow on non-fermentable ethanol-implying recovery of lost mitochondrial function. Through this approach we identified Cardiolipin-specific Deacylase 1 (CLD1), a gene encoding a phospholipase A2 required for cardiolipin acyl remodeling. Interestingly, not all coq7 mutants were suppressed by Cld1p overexpression, and molecular modeling of the mutant Coq7p proteins that were suppressed showed they all contained disruptions in a hydrophobic α-helix that is predicted to mediate membrane-binding. CLD1 overexpression in the suppressible coq7 mutants restored the ratio of DMQ6 to Q6 toward wild type levels, suggesting recovery of lost Coq7p function. Identification of a spontaneous Cld1p loss-of-function mutation illustrated that Cld1p activity was required for coq7 suppression. This observation was further supported by HPLC-ESI-MS/MS profiling of monolysocardiolipin, the product of Cld1p. In summary, our results present a novel example of a lipid remodeling enzyme reversing a mitochondrial ubiquinone insufficiency by facilitating recovery of hypomorphic enzymatic function.
UR - http://www.scopus.com/inward/record.url?scp=84991384144&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84991384144&partnerID=8YFLogxK
U2 - 10.1371/journal.pone.0162165
DO - 10.1371/journal.pone.0162165
M3 - Article
C2 - 27603010
AN - SCOPUS:84991384144
VL - 11
JO - PLoS One
JF - PLoS One
SN - 1932-6203
IS - 9
M1 - e0162165
ER -