AFM Study of Structure of Mitochondrial Membranes in Necrosis and Apoptosis

The ability of mitochondria to potentiate stress-induced necrotic and apoptotic cell death is directly linked to structural changes in inner and/or outer mitochondrial membranes which result in the dramatic increase of their permeability. This increase in permeability during necrosis is caused by the opening of a Permeability Transition Pore - PTP in mitochondrial inner membrane. On the other hand apoptosis induces opening of a large non-selective channel (Mitochondrial Apoptotic Channel - MAC) in the mitochondrial outer membrane. We used Atomic force microscopy to study the structure and organization of native mitochondrial membranes isolated from necrotic and apoptotic cells. We complement our AFM imaging with nanopatricle-based immnunoassays, where mitochondrial membranes are pretreated with nanoparticle-conjugated antibodies for recognition of specific proteins. We will present our data on morphological studies of these membranes and will discuss feasibility of this approach for visualization of mPTP and MAC channels in the native mitochondrial inner membranes (MIM) and mitochondrial outer membranes (MOM) using AFM methods.