PLK1

Polo-like kinase 1 (PLK1) is a protein that in humans is encoded by the PLK1 gene. PLK1 is a member of the polo-like kinase family, a group of serine/threonine kinases that play critical roles in cell cycle progression, mitosis, and cytokinesis. The enzyme's name is derived from its similarity to the polo gene product of Drosophila melanogaster.

Function

PLK1 is essential for the process of mitosis. It is involved in the initiation of mitotic spindle formation, the separation of centrosomes, and the removal of cohesin from chromosome arms, facilitating proper chromosome segregation. Additionally, PLK1 regulates the mitotic exit and cytokinesis, ensuring the successful completion of the cell division process.

PLK1 activity is tightly regulated throughout the cell cycle. It is activated in the late G2 phase and remains active until the M phase, where its activity peaks. The regulation of PLK1 involves several mechanisms, including phosphorylation by Aurora A kinase and cyclin-dependent kinases (CDKs), as well as its interaction with various co-factors and substrates.

Clinical Significance

Due to its pivotal role in cell division, PLK1 has been identified as a potential target for cancer therapy. Overexpression of PLK1 has been observed in various types of cancers, including breast cancer, ovarian cancer, prostate cancer, and colorectal cancer. This overexpression is often associated with poor prognosis and increased aggressiveness of the tumor.

Inhibitors of PLK1 are currently being explored as anticancer agents. These inhibitors aim to selectively target and inhibit the kinase activity of PLK1, thereby inducing apoptosis in cancer cells while sparing normal cells. Several PLK1 inhibitors are in various stages of clinical trials, showing promise as potential therapeutic agents against cancer.

See Also

• Cell cycle
• Mitosis
• Serine/threonine kinase
• Cancer therapy