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Biochim Biophys Acta. 2016 Jan;1857(1):34-45. doi: 10.1016/j.bbabio.2015.10.004. Epub 2015 Oct 19.

Specific degradation of phosphatidylglycerol is necessary for proper mitochondrial morphology and function.

Author information

1
Department of Membrane Biochemistry, Institute of Animal Biochemistry and Genetics, Slovak Academy of Sciences, Ivanka pri Dunaji, Slovakia.
2
Department of Biochemistry, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia.
3
Department of Physiology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA.
4
Microscopy Unit, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
5
Department of Membrane Biochemistry, Institute of Animal Biochemistry and Genetics, Slovak Academy of Sciences, Ivanka pri Dunaji, Slovakia. Electronic address: Maria.Balazova@savba.sk.

Abstract

In yeast, phosphatidylglycerol (PG) is a minor phospholipid under standard conditions; it can be utilized for cardiolipin (CL) biosynthesis by CL synthase, Crd1p, or alternatively degraded by the phospholipase Pgc1p. The Saccharomyces cerevisiae deletion mutants crd1Δ and pgc1Δ both accumulate PG. Based on analyses of the phospholipid content of pgc1Δ and crd1Δ yeast, we revealed that in yeast mitochondria, two separate pools of PG are present, which differ in their fatty acid composition and accessibility for Pgc1p-catalyzed degradation. In contrast to CL-deficient crd1Δ yeast, the pgc1Δ mutant contains normal levels of CL. This makes the pgc1Δ strain a suitable model to study the effect of accumulation of PG per se. Using fluorescence microscopy, we show that accumulation of PG with normal levels of CL resulted in increased fragmentation of mitochondria, while in the absence of CL, accumulation of PG led to the formation of large mitochondrial sheets. We also show that pgc1Δ mitochondria exhibited increased respiration rates due to increased activity of cytochrome c oxidase. Taken together, our results indicate that not only a lack of anionic phospholipids, but also excess PG, or unbalanced ratios of anionic phospholipids in mitochondrial membranes, have harmful consequences on mitochondrial morphology and function.

KEYWORDS:

Mitochondria; Morphology; Phosphatidylglycerol; Respiration; Yeast

PMID:
26482708
PMCID:
PMC4690203
DOI:
10.1016/j.bbabio.2015.10.004
[Indexed for MEDLINE]
Free PMC Article

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