Cardiolipin and mitochondrial cristae organization.
A fundamental question in cell biology, under investigation for over six decades, is the structural organization of mitochondrial cristae. Long known to harbor electron transport chain proteins, crista membrane integrity is key to establishment of the proton gradient that drives oxidative phosphorylation. Visualization of cristae morphology by electron microscopy/tomography has provided evidence that cristae are tube-like extensions of the mitochondrial inner membrane (IM) that project into the matrix space. Reconciling ultrastructural data with the lipid composition of the IM provides support for a continuously curved cylindrical bilayer capped by a dome-shaped tip. Strain imposed by the degree of curvature is relieved by an asymmetric distribution of phospholipids in monolayer leaflets that comprise cristae membranes. The signature mitochondrial lipid, cardiolipin (~18% of IM phospholipid mass), and phosphatidylethanolamine (34%) segregate to the negatively curved monolayer leaflet facing the crista lumen while the opposing, positively curved, matrix-facing monolayer leaflet contains predominantly phosphatidylcholine. Associated with cristae are numerous proteins that function in distinctive ways to establish and/or maintain their lipid repertoire and structural integrity. By combining unique lipid components with a set of protein modulators, crista membranes adopt and maintain their characteristic morphological and functional properties. Once established, cristae ultrastructure has a direct impact on oxidative phosphorylation, apoptosis, fusion/fission as well as diseases of compromised energy metabolism.
Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, CA 94609, United States.
Nikita
N
Ikon
Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, CA 94609, United States. Electronic address: rryan@chori.org.
Robert O
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Ryan
D000217:Acyltransferases; D001798:Blood Proteins / Q000235:genetics / Q000378:metabolism; D002308:Cardiolipins / Q000378:metabolism*; D020558:GTP Phosphohydrolases / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism* / Q000648:ultrastructure; D063154:Mitochondrial Dynamics; D051336:Mitochondrial Membranes / Q000378:metabolism* / Q000648:ultrastructure; D024101:Mitochondrial Proteins / Q000235:genetics* / Q000378:metabolism; D010085:Oxidative Phosphorylation; D010713:Phosphatidylcholines / Q000378:metabolism; D010714:Phosphatidylethanolamines / Q000378:metabolism; D000091402:Prohibitins; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D001798:Blood Proteins; D002308:Cardiolipins; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D000091402:Prohibitins; D012097:Repressor Proteins; C406287:STOML2 protein, human; D014157:Transcription Factors; C483858:phosphatidylethanolamine; D000217:Acyltransferases; C108675:TAFAZZIN protein, human; D020558:GTP Phosphohydrolases; C415198:OPA1 protein, human
Cardiolipin; Cristae; Electron transport chain; Membrane curvature; Mitochondria; Non-bilayer lipid; Phospholipid