p21 Antibody CIP1/823 / p21 WAF1 Monoclonal Antibody [clone CIP1/823] (V2433)

Description

p21 Antibody CIP1/823 / p21 WAF1 Monoclonal Antibody recognizes cyclin-dependent kinase inhibitor 1A, a central regulator of cell cycle progression and cellular responses to stress. Encoded by the CDKN1A gene, p21 is also known as WAF1 and CIP1 and belongs to the CIP/KIP family of cyclin-dependent kinase inhibitors. The protein regulates cell proliferation by interacting with cyclin-CDK complexes and other proteins involved in DNA replication and checkpoint control. Its expression is frequently induced following activation of the p53 pathway, although several p53-independent mechanisms also regulate CDKN1A transcription.

One of the principal functions of p21 involves controlling progression through the G1 and S phases of the cell cycle. By binding cyclin E-CDK2 and cyclin A-CDK2 complexes, p21 can inhibit kinase activity and restrict entry into DNA synthesis. Its relationship with cyclin D-associated CDK4 and CDK6 complexes is more complex because p21 can facilitate their assembly under certain conditions while inhibiting their activity in others. These interactions allow p21 to coordinate cellular proliferation with environmental signals and internal checkpoint mechanisms.

Following DNA damage, stabilization and activation of p53 can increase CDKN1A expression, producing a temporary or sustained cell cycle arrest. This response allows cells to repair damaged DNA before continuing proliferation. Depending on the cellular context, prolonged p21 expression may also contribute to senescence, a relatively stable state of cell cycle withdrawal. However, p21 is not exclusively associated with growth inhibition. Its biological effects depend on expression levels, interacting proteins, post-translational modifications, and subcellular localization.

In addition to regulating cyclin-dependent kinases, p21 interacts with proliferating cell nuclear antigen (PCNA), a central component of DNA replication and repair. This interaction can influence DNA synthesis and the coordination of replication-associated processes. Nuclear p21 is primarily associated with cell cycle inhibition, while cytoplasmic p21 has been implicated in signaling pathways that regulate apoptosis and cellular survival. Phosphorylation, ubiquitination, and other regulatory mechanisms influence p21 stability, localization, and protein interactions.

Altered p21 expression has been observed in numerous cancers and may reflect changes in p53 signaling, cellular differentiation, or checkpoint regulation. Its effects can differ substantially depending on tumor biology and the balance between nuclear and cytoplasmic activities. Research into CDKN1A continues to examine its involvement in cell cycle arrest, senescence, DNA damage responses, and cellular adaptation to stress. NSJ Bioreagents offers this p21 Antibody to support investigations of cell cycle regulation and the molecular mechanisms controlling cellular proliferation.

For additional research into CDKN1A-mediated cell cycle regulation and DNA damage responses, explore our p21 Antibody (V2431), featuring clone DCS-60.2.

Application Notes

Optimal dilution of the p21 Antibody CIP1/823 / p21 WAF1 Monoclonal Antibody to be determined by the researcher.

1. Staining of formalin-fixed tissues requires boiling tissue sections in pH 9 10mM Tris with 1mM EDTA for 10-20 min followed by cooling at RT for 20 min
2. The prediluted format is supplied in a dropper bottle and is optimized for use in IHC. After epitope retrieval step (if required), drip mAb solution onto the tissue section and incubate at RT for 30 min.

Immunogen

Recombinant full-length human protein was used as the immunogen for the p21 antibody.

Storage

Store the p21 antibody at 2-8oC (with azide) or aliquot and store at -20oC or colder (without azide).

Alternate Names

CDKN1A antibody, Cyclin-Dependent Kinase Inhibitor 1A antibody, p21 CIP1 antibody, p21 WAF1 antibody