CD – 95 in apoptosis; the death receptors initiated through –
**Core Concept**
The CD-95, also known as Fas receptor, is a key component in the extrinsic pathway of apoptosis (programmed cell death). It is a death receptor that, upon binding with its ligand FasL, triggers a cascade of intracellular events leading to cell death.
**Why the Correct Answer is Right**
The correct answer is associated with the extrinsic pathway of apoptosis, which is distinct from the intrinsic mitochondrial pathway. The extrinsic pathway is initiated by the binding of death ligands (such as FasL) to their respective death receptors (such as CD-95/Fas). This binding causes the formation of the death-inducing signaling complex (DISC), which activates the caspase cascade, ultimately leading to cell death. The correct answer is involved in this process.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is not directly related to the extrinsic pathway of apoptosis initiated by death receptors.
**Option B:** This option is incorrect because it is associated with the intrinsic mitochondrial pathway of apoptosis, which is a separate process from the extrinsic pathway.
**Option C:** This option is incorrect because it is not directly involved in the initiation of apoptosis through death receptors.
**Clinical Pearl / High-Yield Fact**
Remember that the extrinsic pathway of apoptosis is triggered by external signals, such as death ligands binding to death receptors, whereas the intrinsic pathway is triggered by internal cellular stress or damage.
**Correct Answer:** D.