transcription factor TFIIH holo complex obsolete cyclin-dependent protein kinase activating kinase holoenzyme complex https://github.com/geneontology/go-ontology/issues/26676 true GO:0019907 OBSOLETE. A cyclin-dependent kinase activating kinase complex capable of activating cyclin-dependent kinases by threonine phosphorylation, thus regulating cell cycle progression. consists of a kinase, cyclin and optional assembly factors, in human CDK7, CCNH and MNAT1. CAK activity is itself regulated throughout the cell cycle by T-loop phosphorylation of its kinase component (CDK7 in human). Phosphorylation of serine residues during mitosis inactivates the enzyme. Also capable of CAK phosphorylating the carboxyl-terminal domain (CTD) of RNA polymerase II and other transcription activating proteins, as part of the general transcription factor TFIIH. cellular_component