B-cell lymphoma 2 protein family (Bcl-2 family) (Bcl-2 family)

The B-cell lymphoma 2 (Bcl-2) protein family consists of critical regulators of the intrinsic apoptotic pathway, governing the decision between cell life and death at the mitochondrion [1]. This family is categorized into three groups based on function and Bcl-2 homology (BH) domains: anti-apoptotic proteins (e.g., Bcl-2, Bcl-xL, Mcl-1), pro-apoptotic effectors (Bax, Bak), and pro-apoptotic BH3-only initiators (e.g., Bim, Puma, Bid) [2]. In many malignancies, particularly B-cell lymphomas and leukemias, the overexpression of anti-apoptotic members allows cancer cells to evade programmed cell death and develop resistance to conventional therapies [3]. Therapeutic intervention focuses on BH3 mimetics, which are small molecules designed to occupy the binding grooves of anti-apoptotic proteins, thereby liberating pro-apoptotic effectors to trigger mitochondrial outer membrane permeabilization [4]. The clinical success of the selective Bcl-2 inhibitor Venetoclax has validated this pathway as a major target in oncology, though challenges such as acquired resistance and dose-limiting toxicities like tumor lysis syndrome remain [5].

Other names

Bcl-2 family proteinsB-cell CLL/lymphoma 2 familyApoptosis regulator Bcl-2 family

BH3 mimetics that competitively bind to the hydrophobic groove of anti-apoptotic Bcl-2 family proteins, displacing pro-apoptotic BH3-only proteins and effectors (Bax/Bak) to induce mitochondrial outer membrane permeabilization and apoptosis.