Cdk-activating kinase assembly factor MAT1, centre (IPR015877)

Short name: Cdk-activating_kinase_MAT1_cen

Overlapping homologous superfamilies


Domain relationships



MAT1 (menage a trois 1) is a RING finger protein with a characteristic C3HC4 motif located in the N-terminal domain. This entry represents the central region of MAT1. MAT1 stabilises the cyclin H-CDK7 complex to form a functional CDK-activating kinase (CAK) enzymatic complex which then goes on to activate many of the CDK enzymes intimately involved in the cell cycle [PMID: 11007478]. CDK7 forms a stable complex with cyclin H and MAT1 in vivo only when phosphorylated on either one of two residues (Ser164 or Thr170) in its T-loop. The requirement for MAT1 for the activation of CAK can be by-passed by the phosphorylation of CDK7 on the T-loop. The two mechanisms for CDK7 complex stabilisation and activation (MAT1 addition and T-loop phosphorylation), which can operate independently in vitro, actually cooperate under physiological conditions to maintain complex integrity. With prolonged exposure to elevated temperature, dissociation to monomeric subunits occurs in vivo when CDK7 is dephosphorylated, even in the presence of MAT1 [PMID: 11447116].

The Cyclin H-MAT1-CDK7 complex also forms part of TFIIH, a multiprotein complex required for both transcription and DNA repair.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.