tailieunhanh - Báo cáo khoa học: Changes in specific lipids regulate BAX-induced mitochondrial permeability transition

Recent evidence suggests the existence of lipid microdomains in mitochon-dria, apparently coexisting as structural elements with some of the mito-chondrial permeability transition pore-forming proteins and members of the Bcl-2 family. | ễFEBS Journal Changes in specific lipids regulate BAX-induced mitochondrial permeability transition E. Martinez-Abundis1 N. García1 F. Correa1 M. Franco2 and C. Zazueta1 1 Departamento de Bioquimica Institute Nacionalde Cardiologia Ignacio Chavez Mexico 2 Departamento de Nefrologia Instituto Nacionalde Cardiologia Ignacio Chavez Mexico Keywords BAX cholesterol gangliosides lipid microdomains mitochondrialpermeability transition pore Correspondence C. Zazueta Instituto Nacionalde Cardiologia I. Ch. Departamento de Bioquimica Juan Badiano No. 1 Colonia Seccion XVI Mexico 14080 Fax 52 55 5573 0926 Tel 52 55 5573 2911 1465 E-mail azazuetam@ Received 13 August 2007 revised 17 October 2007 accepted 25 October 2007 doi Recent evidence suggests the existence of lipid microdomains in mitochondria apparently coexisting as structural elements with some of the mitochondrial permeability transition pore-forming proteins and members of the Bcl-2 family. The aim of this study was to investigate the relevance of the main components of membrane microdomains . cholesterol and sphingolipids in activation of the mitochondrial permeability transition pore mPTP by recombinant BAX rBAX . For this purpose we used chemically modified renal cortex mitochondria and renal cortex mitochondria from hypothyroid rats that show a modified mitochondrial lipid composition in vivo. Oligomeric rBAX induced an enhanced permeability conformation in the mPTP of control mitochondria. rBAX failed to induce mPTP opening when the cholesterol and ganglioside content of mitochondria were modified with the chelator methyl-beta-cyclodextrin. Accordingly hypothyroid mitochondria with endogenously lower cholesterol and ganglioside content showed resistance to mPTP opening induced by rBAX. These observations suggest that enriched cholesterol and ganglioside domains in the mitochondrial membranes may determine BAX interaction with the mPTP. An intriguing observation .