Cyclin D

Cyclin D is a protein that plays a key role in cell cycle regulation, specifically in the transition from the resting phase (G0) or the first gap phase (G1) to the DNA synthesis phase (S). It binds to and activates specific enzymes called cyclin-dependent kinases (CDKs), which then modify other proteins to promote cell division. Proper regulation of Cyclin D ensures normal cell growth and division. Abnormal levels can lead to uncontrolled cell proliferation, contributing to cancer development. In short, Cyclin D helps control when a cell prepares to divide, ensuring orderly growth and tissue maintenance.