Before revision:  One of the key components of extrinsically activated apoptosis is the death receptor Fas, which, on binding to its cognate ligand  , oligomerize to form the death-inducing signaling complex , a pivotal trigger of apoptosis .
After revision:  One of the key components of extrinsically activated apoptosis is the death receptor Fas, which, on binding to its cognate ligand FasL , oligomerize to form the death-inducing signaling complex , a pivotal trigger of apoptosis .