Cardiolipin membrane domains in prokaryotes and eukaryotes

Abstract

Summary Cardiolipin (CL) plays a key role in dynamic organization of bacterial and mitochondrial membranes. CL forms membrane domains in bacterial cells, and these domains appear to participate in binding and functional regulation of multi-protein complexes involved in diverse cellular functions including cell division, energy metabolism, and membrane transport. Visualization of CL domains in bacterial cells by the fluorescent dye 10-N-nonyl acridine orange is critically reviewed. Possible mechanisms proposed for CL dynamic localization in bacterial cells are discussed. In the mitochondrial membrane CL is involved in organization of multi-subunit oxidative phosphorylation complexes and in their association into higher order supercomplexes. Evidence suggesting a possible role for CL in concert with ATP synthase oligomers in establishing mitochondrial cristae morphology is presented. Hypotheses on CL-dependent dynamic reorganization of the respiratory chain in response to changes in metabolic states and CL dynamic re-localization in mitochondria during the apoptotic response are briefly addressed.

Unremodeled and Remodeled Cardiolipin Are Functionally Indistinguishable in Yeast

“…Importantly, studies that previously reported abnormal mitochondrial morphology in ⌬crd1 and ⌬taz1 yeast never reported the penetrance of the observed defects (19,52). Furthermore, our results indicate that the genetic background contributes to mitochondrial morphology.…”

“…4 a mitochondrial phospholipid with two phosphate headgroups and four acyl chains, is required for the optimal function of numerous mitochondrial processes, including oxidative phosphorylation (OXPHOS) (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13), protein import (14 -17), establishment of cristae morphology (18,19), fission and fusion (20 -22), and apoptosis (23,24). Despite limited acyl chain specificity of the CL biosynthetic enzymes (25,26), the acyl chain composition of CL within an organism or cell type displays a remarkable degree of homogeneity (27).…”

“…Morphology-Altered mitochondrial morphology has been observed in ⌬crd1 and ⌬taz1 yeast (19,52). To determine what role, if any, CL remodeling plays in the establishment and/or maintenance of mitochondrial morphology, CL remodeling mutants were analyzed by EM (Fig.…”

Multiple modes of interconverting dynamic pattern formation by bacterial cell division proteins

“…We used three different compositions of supported lipid bilayers: E. coli polar lipids (E. coli lipid bilayer), synthetic lipid mixture mimicking the head group composition of the E. coli polar lipids but with a synthetic mixture of 70% double-unsaturated and 30% monounsaturated aliphatic tail groups (18:2 bilayer), and a synthetic lipid mixture with 100% of the monounsaturated aliphatic tail groups (18:1 bilayer). The difference between lipid bilayers was in the lipid raft structure (28)(29)(30)(31) and fluidity of the membrane (SI Domain Structures in the Supported Lipid Bilayer, Fig. S1 A and B).…”

Arrangement of the Respiratory Chain Complexes in Saccharomyces cerevisiae Supercomplex III2IV2 Revealed by Single Particle Cryo-Electron Microscopy

“…The individual complexes contain several tightly bound phospholipid molecules that are integral to the structural integrity of each complex (11)(12)(13). The mitochondrial-specific phospholipid cardiolipin (CL) 5 is required for higher order organization of the individual complexes into supercomplexes (10, 14 -20); also see reviews (3,21). Understanding how the individual complexes are arranged in respirasomes and what role lipids play in respirasome formation and stability will provide information required for understanding the mechanism of electron transfer between individual complexes as well as the basis for dynamics of respiratory chain re-organization in the mitochondrial membrane.…”