The role of nonbilayer phospholipids in mitochondrial structure and function

Mitochondrial structure and function are influenced by the unique phospholipid composition of its membranes. While mitochondria contain all the major classes of phospholipids, recent studies have highlighted specific roles of the non-bilayer forming phospholipids phosphatidylethanolamine (PE) and cardiolipin (CL) in the assembly and activity of mitochondrial respiratory chain (MRC) complexes. The non-bilayer phospholipids are cone-shaped molecules that introduce curvature stress in the bilayer membrane and have been shown to impact mitochondrial fusion and fission. In addition to their overlapping roles in these mitochondrial processes, each non-bilayer phospholipid also plays a unique role in mitochondrial function; for example, CL is specifically required for MRC supercomplex formation. Recent discoveries of mitochondrial PE and CL trafficking proteins and prior knowledge of their biosynthetic pathways have provided targets for precisely manipulating non-bilayer phospholipid levels in the mitochondrial membranes in vivo. Thus, the genetic mutants of these pathways could be valuable tools in illuminating molecular functions and biophysical properties of non-bilayer phospholipids in driving mitochondrial bioenergetics and dynamics. This article is protected by copyright. All rights reserved.