CDK9（cyclin dependent kinase 9），癌症关联基因，基因ID：1025，该基因编码的蛋白是细胞周期蛋白依赖性蛋白激酶（CDK）家族的成员。cdk家族成员与酿酒酵母cdc28和pombe cdc2的基因产物非常相似，被称为重要的细胞周期调节器。这种激酶被发现是多蛋白复合物tak/p-tefb的一个组成部分，它是RNA聚合酶Ⅱ定向转录的延伸因子，通过磷酸化RNA聚合酶Ⅱ最大亚单位的C端域发挥作用。该蛋白与调节亚单位cyclin t或cyclin k形成复合物，并受其调节亚单位cyclin t或cyclin k的调控。发现hiv-1 tat蛋白与该蛋白和cyclin t相互作用，提示该蛋白可能参与艾滋病。The protein encoded by this gene is a member of the cyclin-dependent protein kinase (CDK) family. CDK family members are highly similar to the gene products of S. cerevisiae cdc28， and S. pombe cdc2， and known as important cell cycle regulators. This kinase was found to be a component of the multiprotein complex TAK/P-TEFb， which is an elongation factor for RNA polymerase II-directed transcription and functions by phosphorylating the C-terminal domain of the largest subunit of RNA polymerase II. This protein forms a complex with and is regulated by its regulatory subunit cyclin T or cyclin K. HIV-1 Tat protein was found to in。