3 Types of Pro-apoptotic Proteins

Pro-apoptotic proteins are the proteins that induce and activate the apoptotic pathway. The antagonist of pro-apoptotic proteins are the anti-apoptotic proteins which inhibit and stop the apoptotic pathway. The pro-apoptotic and anti-apoptotic proteins can work together to maintain a dynamic balance between the survival and death of the cell. Today, we will discuss three types of pro-apoptotic proteins.

Pro-apoptotic Protein – Bax

The pro-apoptotic Bax protein is another major player in apoptosis (Mojgan et. al., 2002). Studies have proved that when Bax is activated, it creates discontinuity or pores in the outer mitochondrial membrane to regulate the release of cytochrome c. The intrinsic apoptotic pathway will not be activated in the absence of Bax-activating signals. In addition, cells lack of Bax protein will not undergo apoptosis even though there are death stimuli (Lei et. al., 2006).

Pro-apoptotic Protein – Caspases

Caspases are a family of cysteine proteases that play a crucial role in apoptosis. When the caspases are exposed to a pro-apoptotic signal, the zymogen forms of caspases will proteolytically cleave and activated. The initiator caspases like caspase 8, caspase 9, and caspase 10 can split other caspases. The executioner caspases such as caspase 3, caspase 6 and caspase 7 cleave the death substrates. All caspases consists of a single cysteine at the enzyme catalytic site (Byung et. al., 2002). Both intrinsic and extrinsic pathways trigger pro-apoptotic caspases or pro-caspases via a process called caspase cascade (Avi et. al., 2008).

Pro-apoptotic Protein – p53

The p53 protein is a transcription factor and pro-apoptotic protein. It proliferates the transcriptional expression of several genes that involved when react to genotoxic agents like ionizing radiation and chemical therapeutic drugs. The p53 protein initiates the cell cycle arrest and DNA damage repair. If the cells cannot be repaired, the p53 protein will activates cell death programs and the cells then go through the apoptosis. Hence, p53 protein is a tumor suppressor protein against cancer development. The effective ways to prevent tumor growth and discard cancers are inhibit the cell proliferation and promote the apoptosis in tumors. Conventionally, chemotherapeutic agents that used to induce apoptosis are mediated mostly via p53-dependent pathways. Yet, most of human tumors have p53 mutations and inactivation (Luo et. al., 2008). The p53 protein activates the expression of pro-apoptotic proteins, such as Bax and down regulates the expression of the anti-apoptotic protein like Bcl-2 (Byung et. al., 2002).

In conclusion, many therapeutic strategies can be designed to treat the cancer by regulating the pro-apoptotic and anti-apoptotic proteins. Cancer research on apoptotic pathway will really help us to design the most effective cancer treatment.

3 Types of Pro-apoptotic Proteins is a post from: Cytogenetics and Cancer Research