| Protein Name | BCL2-Like 11 (BIM) |
|---|---|
| Gene | [BCL2L11](/genes/bcl2l11) |
| UniProt ID | O43521 |
| Protein Size | 198 amino acids (~22 kDa); multiple isoforms (BIM EL, BIM L, BIM S) |
| Subcellular Localization | Cytosol (inactive); mitochondria (upon activation) |
| Protein Family | BCL-2 family (BH3-only, pro-apoptotic) |
| PDB Structures | 2K7W, 2P50, 3UW7 |
BCL2L11 (BIM) is a potent pro-apoptotic protein of the BCL-2 family that functions as a key initiator of mitochondrial apoptosis. BIM is unique among BH3-only proteins in its ability to activate BAX/BAK directly while also inhibiting all anti-apoptotic BCL-2 proteins.
BIM has the BH3-only protein structure:
BH3 Domain (aa 146-164): Critical for interactions with BCL-2 family proteins; the "death domain"
Multiple Isoforms:
Dimerization Domain: Enables BIM to form heterodimers with BCL-2 proteins
Dysfunction Domain: Unique region that allows direct activation of BAX
BIM performs essential pro-apoptotic functions:
Apoptosis Initiation: BIM is the most potent direct activator of BAX/BAK-mediated MOMP[1].
BH3 Mimetic Activity: BIM can bind and neutralize all anti-apoptotic BCL-2 proteins.
Developmental Cell Death: Critical for elimination of autoreactive lymphocytes and proper development.
Tissue Homeostasis: Regulates cell numbers in various tissues through apoptosis.
Stress Sensing: Activated by cellular stress signals including growth factor withdrawal.
BIM is being explored as a therapeutic target:
Therapeutic Paradox: In cancer, we want to inhibit BIM function (to prevent cell death), but in neurodegeneration, we want to inhibit BIM function (to prevent neuronal death).
BIM interacts with: