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Biophysics of Proteins at Surfaces: Assembly, Activation, Signaling
Poster Abstracts
11-POS
Board 11
Investigating the Membrane Topology of Proapoptotic BAX
Hector Flores Romero
, Juan Garcia-Valero, Olatz Landeta, Ane Landajuela, Itsasne Bustillo-
Zabalbeitia, Miguel Garcia-Porras, Oihana Terrones, Gorka Basañez.
Biophysics Unit CSIC-UPV/EHU, Barrio Sarriena, Leioa 48940, Spain.
Mitochondrial outer membrane (MOM) permeabilization is the point of no return in many forms
of apoptotic cell death. The BCL2 family member BAX is a crucial effector of MOM
permeabilization that adopts an inactive conformation in the cytosol of healthy cells. It is well
established that functional BAX activation is a complicated process, initiated by translocation of
BAX to the MOM and culminating with assembly of BAX into a protein-permeable apoptotic
pore. However, most of our current structural knowledge of BAX originates from studies in
membrane-free environments. Given the inherent complexity of the cellular apoptotic network,
here we used the single-cysteine accessibility methodology applied to in vitro reconstituted
systems (MOM-like liposomes and isolated mitochondria) to gain structural and mechanistic
information about BAX in a membrane environment.