CDK9 (PITALRE): A multifunctional cdc2-related kinase

CDK9 is a cdc2-related kinase protein. Previously named PITALRE, this prote in is a serine-threonine kinase involved in many physiological processes. U nlike most of the cdc2-like kinases, its activity is not cell cycle-regulat ed. CDK9 acts preferentially in processes different from cell-cycle regulat ion, such as differentiation. Its cyclin partners, cyclins of T family, rec ently have been isolated. CDK9 immunoprecipitates with several unidentified polypeptides that may regulate its kinase activity. CDK9 has been shown to associate with the HIV-Tat protein, suggesting a possible involvement in A IDS. CDK9 recently was shown to be responsible for the kinase activity asso ciated with the TAK complex and with the P-TEFb complex, suggesting activit y also in the transcription process, J Cell Physiol 177:501-506, 1998. (C) 1998 Wiley-Liss, Inc.