Membrane lipid reshaping underlies oxidative stress sensing by the mitochondrial proteins UCP1 and ANT1

Abstract

AbstractOxidative stress and ROS are important players in the pathogenesis of several diseases. Besides the direct modification of proteins, ROS modify lipids with negative spontaneous curvature, such as phosphatidylethanolamine (PE), producing PE adducts and lysolipids. The formation of PE-adducts potentiates the protonophoric activity of the uncoupling protein 1 (UCP1), but the molecular mechanism remains obscure. Here, we connected the ROS-mediated lipid shape alteration with the membrane mechanical properties and function of UCP1 and adenine nucleotide translocase 1 (ANT1). We found that lysophosphatidylcholines (OPC and MPC) and PE adducts decrease a bending modulus in lipid bilayers and increase the protonophoric activity of both proteins. Furthermore, MD simulations revealed that modified PEs and lysolipids alter the membrane lateral pressure profile in the same direction and range, indicating that modified PEs act as lipids with positive spontaneous curvature. Both results indicate that oxidative stress decreases stored curvature elastic stress (SCES) in the lipid bilayer membrane. In conclusion, we demonstrate that UCP1 and ANT1 sense SCES and propose a new regulatory mechanism for the function of these proteins.