Uterine leiomyoma-linked MED12 mutations disrupt mediator-associated CDK activity.
Abstract
Somatic mutations in exon 2 of the RNA polymerase II transcriptional Mediator subunit MED12 occur at very high frequency (∼70%) in uterine leiomyomas. However, the influence of these mutations on Mediator function and the molecular basis for their tumorigenic potential remain unknown. To clarify the impact of these mutations, we used affinity-purification mass spectrometry to establish the global protein-protein interaction profiles for both wild-type and mutant MED12. We found that uterine leiomyoma-linked mutations in MED12 led to a highly specific decrease in its association with Cyclin C-CDK8/CDK19 and loss of Mediator-associated CDK activity. Mechanistically, this occurs through disruption of a MED12-Cyclin C binding interface that we also show is required for MED12-mediated stimulation of Cyclin C-dependent CDK8 kinase activity. These findings indicate that uterine leiomyoma-linked mutations in MED12 uncouple Cyclin C-CDK8/19 from core Mediator and further identify the MED12/Cyclin C interface as a prospective therapeutic target in CDK8-driven cancers.
Genome-Scale Biology Program and Department of Pathology, Haartman Institute, University of Helsinki, Biomedicum, P.O. Box 63 (Haartmaninkatu 8), Helsinki FIN-00014, Finland.Department of Molecular Medicine, Institute of Biotechnology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, Mail Code 8257, STRF, San Antonio, TX 78229-3900, USA.Institute of Biotechnology, University of Helsinki, Viikinkaari 1, P.O. Box 65, Helsinki FIN-00014, Finland.Department of Molecular Medicine, Institute of Biotechnology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, Mail Code 8257, STRF, San Antonio, TX 78229-3900, USA.Genome-Scale Biology Program and Department of Pathology, Haartman Institute, University of Helsinki, Biomedicum, P.O. Box 63 (Haartmaninkatu 8), Helsinki FIN-00014, Finland; Department of Computer Science, University of Helsinki, P.O. Box 68, Helsinki FIN-00014, Finland.Department of Molecular Medicine, Institute of Biotechnology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, Mail Code 8257, STRF, San Antonio, TX 78229-3900, USA.Genome-Scale Biology Program and Department of Medical Genetics, Haartman Institute, University of Helsinki, Biomedicum, P.O. Box 63 (Haartmaninkatu 8), Helsinki FIN-00014, Finland.Department of Molecular Medicine, Institute of Biotechnology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, Mail Code 8257, STRF, San Antonio, TX 78229-3900, USA.Genome-Scale Biology Program and Department of Pathology, Haartman Institute, University of Helsinki, Biomedicum, P.O. Box 63 (Haartmaninkatu 8), Helsinki FIN-00014, Finland.Institute of Biotechnology, University of Helsinki, Viikinkaari 1, P.O. Box 65, Helsinki FIN-00014, Finland.Genome-Scale Biology Program and Department of Pathology, Haartman Institute, University of Helsinki, Biomedicum, P.O. Box 63 (Haartmaninkatu 8), Helsinki FIN-00014, Finland; Science for Life Laboratory, Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm 14183, Sweden.Genome-Scale Biology Program and Department of Medical Genetics, Haartman Institute, University of Helsinki, Biomedicum, P.O. Box 63 (Haartmaninkatu 8), Helsinki FIN-00014, Finland.Genome-Scale Biology Program and Department of Medical Genetics, Haartman Institute, University of Helsinki, Biomedicum, P.O. Box 63 (Haartmaninkatu 8), Helsinki FIN-00014, Finland.Genome-Scale Biology Program and Department of Medical Genetics, Haartman Institute, University of Helsinki, Biomedicum, P.O. Box 63 (Haartmaninkatu 8), Helsinki FIN-00014, Finland.Department of Biochemistry, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA.Genome-Scale Biology Program and Department of Medical Genetics, Haartman Institute, University of Helsinki, Biomedicum, P.O. Box 63 (Haartmaninkatu 8), Helsinki FIN-00014, Finland.Institute of Biotechnology, University of Helsinki, Viikinkaari 1, P.O. Box 65, Helsinki FIN-00014, Finland. Electronic address: markku.varjosalo@helsinki.fi.Genome-Scale Biology Program and Department of Pathology, Haartman Institute, University of Helsinki, Biomedicum, P.O. Box 63 (Haartmaninkatu 8), Helsinki FIN-00014, Finland; Science for Life Laboratory, Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm 14183, Sweden. Electronic address: jussi.taipale@ki.se.Department of Molecular Medicine, Institute of Biotechnology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, Mail Code 8257, STRF, San Antonio, TX 78229-3900, USA. Electronic address: boyer@uthscsa.edu. MeSH
Cyclin CCyclin-Dependent Kinase 8Cyclin-Dependent KinasesFemaleHEK293 CellsHumansLeiomyomaMediator ComplexMutagenesis, Site-DirectedProtein BindingUterine Neoplasms
Pub Type(s)
Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
