**APAF1**
**Definition**
APAF1 (Apoptotic Protease Activating Factor 1) is a human gene encoding a key protein involved in the intrinsic pathway of apoptosis. It functions as a central component in the formation of the apoptosome, which activates caspases leading to programmed cell death.
**Article**
### Structure and Function
APAF1 is a cytoplasmic protein that contains several functional domains, including a caspase recruitment domain (CARD), a nucleotide-binding and oligomerization domain (NOD), and WD40 repeats. Upon cellular stress or damage, cytochrome c is released from mitochondria and binds to APAF1, triggering its oligomerization into a heptameric apoptosome complex.
### Role in Apoptosis
The apoptosome recruits and activates procaspase-9, initiating a caspase cascade that results in apoptosis. This process is essential for maintaining cellular homeostasis and eliminating damaged or potentially harmful cells.
### Clinical Significance
Dysregulation of APAF1 has been implicated in various diseases, including cancer and neurodegenerative disorders, where impaired apoptosis contributes to disease progression.
**Meta Description**
APAF1 is a crucial protein in the intrinsic apoptosis pathway, forming the apoptosome to activate caspases and regulate programmed cell death. Its function is vital for cellular homeostasis and disease prevention.