Menage A Trois Homolog 1 (MNAT1)

Cyclin-dependent kinases (CDKs), which play an essential role in cell cycle control of eukaryotic cells, are phosphorylated and thus activated by the CDK-activating kinase (CAK). CAK is a multisubunit protein that includes CDK7, cyclin H (CCNH), and MAT1. MAT1 is involved in the assembly of the CAK complex.The cDNA encoded a 309-amino acid polypeptide with a relative mass of 35.8 kD. The human MAT1 amino acid sequence shares 95%, 79%, and 51% identity with sequences of mouse, frog, and starfish Mat1, respectively. Within the zinc-binding RING finger region, the sequences of all 4 species are nearly identical. Northern blot analysis revealed that the human MAT1 gene expressed varied levels of a 1.6-kb transcript in many tissues and cell lines.