The MAT1 cyclin-dependent kinase-activating kinase (CAK) assembly/targeting factor interacts physically with the MCM7 DNA licensing factor

MAT1 (menage a trois1) functions as an assembly/targeting factor of CAK (cyclin-dependent kinase-activating kinase). In a search for MAT1-interacting proteins using yeast two-hybrid system, MCM7 (minichromosome maintenance 7), a member of a family of DSA licensing factors, was identified. The physical interaction between MAT1 and MCM7 was confirmed in vivo in yeast cells and verified with in vitro protein binding assays. Further studies showed the RING-finger motif of MAT1 is not required for the interaction with MCM7, while the C-terminal domain of MAT1 is indispensable. Immunoprecipitation of MCM7 in human osteosarcoma MG63 cells demonstrated that MCM7 associates with the CAK complex in vivo. (C) 2000 Federation of European Biochemical Societies, Published by Elsevier Science B.V. All rights reserved.