Borealin

Borealin is a protein that is a component of the chromosomal passenger complex (CPC), which plays a crucial role in cell division. The CPC is essential for proper chromosome alignment, segregation, and cytokinesis during mitosis and meiosis.

Structure and Function

Borealin, also known as CDCA8 (Cell Division Cycle Associated 8), is one of the four core components of the chromosomal passenger complex, along with Aurora B kinase, INCENP (Inner Centromere Protein), and Survivin. Borealin is involved in the regulation of the CPC's localization and function during cell division. The primary function of Borealin is to ensure the correct attachment of microtubules to the kinetochores, which are protein structures on the chromosome where the spindle fibers attach during cell division. Borealin also plays a role in the activation of Aurora B kinase, which is crucial for the correction of improper microtubule-kinetochore attachments and the regulation of the mitotic checkpoint.

Role in Cell Division

During mitosis, Borealin is required for the proper localization of the CPC to the centromeres and the central spindle. It helps in the stabilization of the mitotic spindle and ensures accurate chromosome segregation. Borealin's interaction with other CPC components is vital for the phosphorylation of various substrates by Aurora B kinase, which is necessary for the progression of mitosis. In meiosis, Borealin functions similarly to ensure the accurate segregation of homologous chromosomes and sister chromatids. Its role is critical in maintaining genomic stability and preventing aneuploidy, a condition where cells have an abnormal number of chromosomes.

Clinical Significance

Dysregulation of Borealin and other CPC components can lead to chromosomal instability, which is a hallmark of many cancers. Overexpression or mutations in the Borealin gene (CDCA8) have been associated with various types of cancer, including breast cancer, lung cancer, and colorectal cancer. As a result, Borealin is considered a potential target for cancer therapy, and research is ongoing to develop inhibitors that can modulate its function.

Related Pages

• Chromosomal passenger complex
• Aurora B kinase
• INCENP
• Survivin
• Mitosis
• Meiosis
• Kinetochores
• Microtubules
• Aneuploidy
• Cancer