The protein encoded by Prc1 is involved in cytokinesis and has been shown to be the substrate for a variety of cyclin-dependent kinases (CDKs), and it is present at high levels during the S and G2/M phases of mitosis, but decreases sharply when cells enter the G1 phase.[37]Ccna2 encodes a highly conserved cyclin protein that promotes transition through G1/S and G2/M by activating CDK2.[38] It has been found that G2/M arrest in renal tubular epithelial cells leads to renal fibrosis by activating JNK signals and upregulating the production of profibrotic cytokines. This evidence concerns the gene MAPK8 and renal fibrosis.