P21: 5-10mg*10 vials

Product Description: P21

Introduction
P21, also known as Cyclin-dependent kinase inhibitor 1A (CDKN1A), is a well-known protein that plays a significant role in cellular processes, particularly in the regulation of the cell cycle. It is widely studied in scientific research for its involvement in various cellular mechanisms, including cell cycle arrest, apoptosis, and cellular stress response. Available in a high-purity form, P21 is used in laboratory experiments to further understand its role in cellular biology, its interactions with other proteins, and its potential applications in a variety of research fields.

What is P21?
P21 is a cyclin-dependent kinase inhibitor (CDKI), primarily responsible for controlling the progression of the cell cycle. It is encoded by the CDKN1A gene and functions to inhibit cyclin-dependent kinases (CDKs), specifically those involved in cell cycle progression at the G1/S checkpoint. P21 is an important regulatory molecule that can either halt cell cycle progression or induce cell death, depending on the surrounding cellular conditions. Its activity is modulated in response to DNA damage, oxidative stress, and other cellular signals.

P21 is a key player in cellular responses to DNA damage and can also contribute to processes such as cellular senescence and differentiation. Researchers often study P21 to gain insight into mechanisms of cell cycle control, tumor suppression, and the cellular stress response.

Potential Different Names

• Cyclin-dependent kinase inhibitor 1A (CDKN1A)
• WAF1 (Wild-type p53-activated fragment 1)
• Cip1 (Cyclin-dependent kinase inhibitor protein 1)
• P21Cip1
• p21WAF1/Cip1
• CDK inhibitor 1A

Chemical Formula
The chemical formula for the P21 protein varies depending on the specific isoform and its post-translational modifications. However, the molecular weight typically ranges around 21 kDa for the full-length protein.

Structure
P21 is a relatively small protein composed of 164 amino acids. It has a well-defined structure that includes a cyclin-binding motif responsible for its interaction with cyclin-dependent kinases (CDKs). The protein’s structure includes several functional domains, including:

• The CDK-binding domain: P21 interacts with the CDK-cyclin complex, effectively inhibiting its activity and thereby arresting cell cycle progression.
• The N-terminal domain: This region is responsible for p21's ability to bind to and inhibit cyclin-CDK complexes.
• A C-terminal domain: This domain is involved in its stability and regulation, and its phosphorylation can influence P21's activity.

The structure of P21 enables it to interact with a range of proteins, including cyclins, CDKs, and tumor suppressor proteins like p53, which regulates P21’s expression.

How Does It Work?
P21 exerts its primary function by inhibiting cyclin-dependent kinases (CDKs), which are crucial for the progression of the cell cycle. Under normal conditions, CDKs interact with cyclins to form active complexes that drive the cell through various stages of the cell cycle, particularly the G1 to S phase transition. P21 binds to CDK-cyclin complexes and blocks their activity, thereby preventing the cell from progressing through the cell cycle.

The activity of P21 is tightly regulated by several factors:

• p53 regulation: P21 is transcriptionally activated by the tumor suppressor protein p53, particularly in response to DNA damage. In such conditions, p53 activates the expression of P21, which then inhibits CDKs to prevent damaged cells from progressing through the cell cycle.
• DNA damage response: When DNA damage occurs, P21 is upregulated as part of the cell’s mechanism to halt the cell cycle, allowing time for repair.
• Cellular stress response: P21 is also involved in cellular responses to oxidative stress, and its levels can be modulated in response to various types of stress.

By binding to CDK-cyclin complexes, P21 helps maintain cell cycle checkpoints, ensuring that cells do not divide with damaged DNA, which could lead to genomic instability. Additionally, P21 has roles in other cellular processes, including differentiation, apoptosis, and senescence.

Conclusion
P21 is a cyclin-dependent kinase inhibitor that plays a central role in regulating the cell cycle, responding to DNA damage, and mediating cellular stress responses. Through its ability to bind and inhibit CDK-cyclin complexes, P21 helps control cell cycle progression, particularly at the G1/S checkpoint. It is a key protein in the study of tumor suppression, cellular senescence, and DNA repair mechanisms. Research on P21 continues to provide valuable insights into cellular regulation and cancer biology.

Disclaimer
This product is intended for laboratory and scientific research purposes only. It is not for human consumption or medical use. All information provided is for research and educational purposes only and does not make any claims regarding the effects or outcomes associated with the use of P21. Researchers should follow appropriate laboratory safety protocols when handling this product. Always use under the guidance of trained professionals in a controlled laboratory setting.