Bcl-xL: Proteins and Enzymes

Bcl-x is a member of the Bcl-2 family of proteins that regulates outer mitochondrial membrane permeability. Alternative splicing results in two distinct Bcl-x isoforms. Bcl-xL (long) is an anti-apoptotic protein that prevents release of Cytochromec from the mitochondrial intermembrane space into the cytosol. Bcl-xs (short) is a pro-apoptotic member that can initiate programmed cell death.