The Bcl-2 family proteins are classified into three main categories based on their functions and structural characteristics: 1. Anti-apoptotic Proteins: These proteins promote cell survival by inhibiting apoptosis. Members include Bcl-2, Bcl-xL, and Mcl-1. 2. Pro-apoptotic Effector Proteins: These proteins promote apoptosis by permeabilizing the mitochondrial outer membrane. Members include Bax, Bak, and Bok. 3. Pro-apoptotic BH3-only Proteins: These proteins act as sensors and initiators of apoptosis, often in response to cellular stress. Members include Bad, Bid, Puma, and Noxa.
