The Role of 14-3-3 in the Signaling of Cardiac Hypertrophy

Ellis, Joel J., The Role of 14-3-3 in the Signaling of Cardiac Hypertrophy. Master of Science (Biotechnology), January, 2002, 97pp., 21 illustrations, bibliography, 46 titles. The METF2 family of transcription factors is regulated by class II histone deacetylaces in the nucleus. MEF2-dependent gene expression in cardiomyocytes is augmented by the 14-3-3 chaperone family which binds and sequesters class II HDACs in the cytoplasm upon the activation of CaM kinase I & IV. A 14-3-3β mutant was made by conservatively substituting aspartate for serine 60 and serine 65. In MEF2 enhancer-reporter transfection assays, expression of the 14-3-3β double mutant silenced transcription mediated by CaM KI & IV in both cardiomyocytes and vascular smooth muscle cells. Co-expression of the 14-3-3β double mutant was also able to suppress MEF2 enhancer activation by phenylephrine in cardiomyocytes and vascular smooth muscle cells. Mammalian two-hybrid cloning of the 14-3-3β wild-type and double mutant genes will allow analysis of the protein-protein interaction between the different 14-3-3β monomers. These data suggest that 14-3-3β plays a critical role in the silencing of MEF2 mediated hypertrophy-sensitive gene transcription.