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.
BH3-only protein, also called Bcl-2-like protein 11, Bim, of 198 aas and 1 C-terminal TMS; induces apoptosis and anoikis (Fukazawa et al. 2004). Different isoforms have differing activities (Marani et al. 2002). Isoform Bim-alpha3 induces apoptosis, possibly through a caspase-mediated pathway, but isoforms BimAC and BimABC lack the ability to induce apoptosis.
Bim of Homo sapiens
Bcl-2 interacting mediator of cell death of 176 aas and one C-terminal TMS.
Bim of Danio rerio (Zebrafish) (Brachydanio rerio)
Bcl-2-like protein 11 of 166 aas and 1 C-terminal TMS
Bcl-2-like protein of Callorhinchus milii (Ghost shark)