Adenosine Triphosphate (ATP) Binding Motif forms a cleft between the N- and C-terminal lobes and is highly conserved among CDKs
The major cyclin partner of CDK9, cyclin T (‘T’ named after the first letter of HIV TAT), has a close similarity to cyclin C and cyclin H. HIV TAT interacts only with cyclin T1 in complex with CDK9 to mediate HIV transcription
CDK9-cyclin T2a interacts directly with
myoblast determination protein 1 (MyoD)
CDK9-cyclin T1 activates muscle
differentiation programs by stimulating the transcription
program of myocyte enhancer factor 2 [MEF2]
CDK9-cyclin T1 is also required for the differentiation of monocytes, lymphocytes, adipocytes, and neurons.