https://wikimd.org/index.php?action=history&feed=atom&title=Cyclin_B1Cyclin B1 - Revision history2026-04-26T13:44:09ZRevision history for this page on the wikiMediaWiki 1.44.2https://wikimd.org/index.php?title=Cyclin_B1&diff=5621796&oldid=prevPrab: CSV import2024-04-17T23:50:36Z<p>CSV import</p>
<p><b>New page</b></p><div>[[Image:Nsp-cellcycle-5-3-5_8.jpg|Nsp-cellcycle-5-3-5 8|thumb]] '''Cyclin B1''' is a [[protein]] that in humans is encoded by the ''CCNB1'' gene. It is a regulatory protein involved in [[mitosis]], the process that leads to the division of a [[cell]] into two daughter cells. Cyclin B1 belongs to the [[cyclin]] family, a group of proteins that control the progression of cells through the [[cell cycle]] by activating [[cyclin-dependent kinase]] (CDK) enzymes.<br />
<br />
== Function ==<br />
Cyclin B1 plays a critical role in controlling the cell cycle at the [[G2 phase|G2]]/[[Mitosis|M]] transition. It forms a complex with [[CDK1]] (also known as CDC2), and this complex is necessary for the initiation of [[mitosis]]. The activity of the cyclin B1-CDK1 complex is regulated by several mechanisms, including the synthesis and degradation of cyclin B1, phosphorylation, and dephosphorylation. The activation of this complex leads to the phosphorylation of various proteins involved in [[chromosome]] condensation, [[nuclear envelope]] breakdown, and the formation of the [[mitotic spindle]], which are essential steps in mitosis.<br />
<br />
== Regulation ==<br />
The levels of cyclin B1 begin to rise during the [[S phase]] of the cell cycle, peak in the G2 phase, and rapidly decrease as cells exit mitosis. The destruction of cyclin B1 is mediated by the [[anaphase-promoting complex]] (APC/C), an E3 [[ubiquitin ligase]] that targets cyclin B1 for degradation by the [[proteasome]]. This degradation is crucial for the exit from mitosis and the completion of the cell cycle.<br />
<br />
== Clinical Significance ==<br />
Abnormal expression of cyclin B1 has been associated with various [[cancer]]s, including [[breast cancer]], [[colorectal cancer]], and [[lung cancer]]. Overexpression of cyclin B1 can lead to uncontrolled cell proliferation, a hallmark of cancer. Therefore, cyclin B1 is considered a potential target for cancer therapy, and efforts are underway to develop drugs that can modulate its activity.<br />
<br />
== See Also ==<br />
* [[Cyclin]]<br />
* [[Cell cycle]]<br />
* [[Mitosis]]<br />
* [[Cyclin-dependent kinase]]<br />
<br />
[[Category:Cell cycle]]<br />
[[Category:Proteins]]<br />
{{medicine-stub}}</div>Prab