The protein encoded by CCNK (Cyclin K) is a member of the transcription cyclin family. These cyclins may regulate transcription through their association with and activation of cyclin-dependent kinases (CDK) that phosphorylate the C-terminal domain (CTD) of the large subunit of RNA polymerase II. CCNK product may play a dual role in regulating CDK and RNA polymerase II activities. CCNK is a Protein Coding gene. Among its related pathways are Formation of HIV elongation complex in the absence of HIV Tat and HIV Life Cycle.