CyclinC Protein

Cyclin C is a member of the cyclin family of proteins and interacts with the cyclin-dependent kinase 8 (CDK8) and induces the phophorylation of the carboxy-terminal domain of the large subunit of RNA polymerase II. The mRNA levels of Cyclin C fluctuate during the cell cycle and peak at the G1 phase. Cyclin C acts as a critical regulator of the G0/G1 transition of human Hematopoietic stem cells (1). Cyclin C can also combine with CDK3 to stimulate Rb phosphorylation at S807/811 during the G0/G1 transition, and this phosphorylation is required for cells to exit G0 efficiently (2).