Function
Regulatory subunit of the cyclin-dependent kinase pair (CDK9/cyclin T) complex, also called positive transcription elongation factor B (P-TEFB), which is proposed to facilitate the transition from abortive to production elongation by phosphorylating the CTD (carboxy-terminal domain) of the large subunit of RNA polymerase II (RNAP II). The activity of this complex is regulated by binding with 7SK snRNA (By similarity). Plays a role during muscle differentiation; P-TEFB complex interacts with MYOD1; this tripartite complex promotes the transcriptional activity of MYOD1 through its CDK9-mediated phosphorylation and binds the chromatin of promoters and enhancers of muscle-specific genes; this event correlates with hyperphosphorylation of the CTD domain of RNA pol II (PubMed:16245309, PubMed:23060074, PubMed:12037670). In addition, enhances MYOD1-dependent transcription through interaction with PKN1 (By similarity). Involved in early embryo development (PubMed:19364821).
Sequence
MASGRGASSRWFFTREQLENTPSRRCGVEADEELSHRQQAANLIQDMGQRLNVSQLTINTAIVYMHRFYMHHSFTKFNRNIISPTALFLAAKVEEQARKLEHVIKVAHACLHPLEPLLDTKCDAYLQQTQELVLLETIMLQTLGFEITIEHPHTDVVKCTQLVRASKDLAQTSYFMATNSLHLTTFCLQYKPTVIACVCIHLACKWSNWEIPVSTDGKHWWEYVDPTVTLELLDELTHEFLQILEKTPSRLKRIRNWRAMAKKPKVDGQVSETPLLGSSLVQNSILVDSVTGVPANPSFQKPSTSTFPAPIPLNSGSTSVQDSRASDNLSVLAAGMPSTSYSLSSHQEWPQHPDSARTDPVYTQKQEATLSGSQYISFQQGPSMALHSGLHHRPDKVADHSSAKQEYTHKAGSSKHHGPIPATPGMLPQKMSLDKYREKRKLETLDVDTRDHYLAAHAEQQHKHGPAQAVTGTSVTSPIKMKLPLTNSDRPEKHVAEKKERSGSLKLRIPIPPPDKGPSKEELKMKIKVASSERHSSSDEGSGKSKHSSPHISRDHKEKHKEHPANRHHSSHKYLHMHSGGSKHTADGMPPTVLRSPVGLGPEGVSSASSARKKLHSSEASHNHHSKMSKSSKSAGSSSSSSSVKQYLSSHSSVFNHPLPPPPPVTYQVGYGHLSTLVKLDKKPVEPHGPEANHEYSTSSQHMDYKDTFDMLDSLLSAQGMNM