BID (Intermediate Domain) Blocking Peptide

Bid is a member of the Bcl-2 family of proteins that regulates outer mitochondrial membrane permeability. Bid is a pro-apoptotic member that causes cytochrome c to be released from the mitochondria intermembrane space into the cytosol. In healthy cells Bid is cytosolic. In response to Fas ligand or TNF Bid is cleaved by caspase-8 and it then relocates to the mitochondria outer membrane. Cleavage of Bid by caspase-8 generates a new N-terminal that contains a terminal glycine. It appears that the glycine is myristoylated and myristoylation serves to target Bid to the mitochondria. Bid may then interact with another pro-apoptotic Bcl-2 family member Bak. Interaction of Bid with Bak causes altered mitochondrial membrane permeability. A 9 - 13 amino acid stretch called the BH3 region (Bcl-2 homology region) appears to mediate the Bid interaction with other Bcl-2 family members. Bid is neutralized by binding to the anti-apoptotic member Bcl-x.