m biophys's List: mito morphology themodynamic proj

357-Pos A Free Energy Model For The Observed Morphologies Of The Crista Membrane Of Mitochondria

Arlette R. Baljon, Mariam Ghochani, Peter Salamon, Jim Nulton, Avinoam Rabinovitch, Terry Frey

San Diego State University, San Diego, CA, USA

Board B190

Electron tomograms have revealed that in normal mitochondria the crista membrane contains both tubular and flat lamellar components. Using a simplified model, we have been able to predict the conditions under which the observed morphologies can be obtained by minimizing the system’s free energy. The model predicts that the tubular structures are stabilized by tensile forces of the order of 10 pN, comparable to those typical of motor proteins. The model also predicts reasonable values for the pressure difference across the crista membrane and its surface tension. Currently we are investigating whether our free energy model can predict a more recently observed morphology ^*, a transformation of the mitochondrial inner membrane into multiple vesicular matrix compartments observed during programmed cell death (apoptosis) in HeLa cells treated with etoposide. We plan to report these results as well.