NOXA also known as ARP, PMAIP1 is a pro-apoptotic member of the Bcl-2 family, contains the Bcl-2 homology 3 (BH3) region, but does not contain other BH domains. NOXA plays a crucial role in regulating programmed cell death, which is vital for maintaining cellular homeostasis and preventing tumorigenesis. NOXA contains the Bcl-2 homology 3 (BH3) domain, which is essential for promoting apoptosis, while lacking other BH domains present in anti-apoptotic proteins. NOXA is selectively localized to the mitochondria, where NOXA interacts with other Bcl-2 family members to modulate apoptotic signaling pathways. This mitochondrial localization positions NOXA to directly influence the release of cytochrome c and other pro-apoptotic factors, thereby initiating the apoptotic cascade.