8.A.69 The Pro-apoptotic Bcl-2-Family Protein Bim (Bim) Family
The pro-apoptotic Bcl-2-family protein Bim belongs to the BH3-only proteins known as initiators of apoptosis. Bim is constitutively inserted in the outer mitochondrial membrane via a C-terminal transmembrane anchor from where it can activate the effector of cytochrome c-release, Bax (Frank et al. 2015). Interactions of Bim with Tom70, Tom20 and more weakly with Tom40, all components of the Translocase of the Outer Membrane (TOM; TC# 3.A.8) have been documented. Protein receptors may be involved in the import process. In isolated yeast mitochondria, lack of Tom70 or the TOM-components Tom20 or Tom22 did not affect the import of Bim into the outer mitochondrial membrane. In yeast, expression of Bim can sensitize the cells to Bax-dependent killing, but the physiological role of the Bim-TOM-interaction remains unclear.