UC Davis

The L-type Ca2+ channel (CaV1.2) is essential for cardiac excitation-contraction coupling. Alterations in CaV1.2 expression, localization, or function can underlie cardiac dysfunction found in aging and heart disease; thus the regulatory mechanisms that tune CaV1.2 expression to meet contractile demand are a crucial area of research. This dissertation work highlights the function of two proteins that regulate CaV1.2 trafficking: 14-3-3 and BIN1. We used a range of techniques including confocal imaging, proximity ligation assays, super-resolution imaging, In vivo echocardiography, and co-immunoprecipitation to explore the dynamics of this regulation. Our work elucidates a novel mechanism where 14-3-3 interacts with CaV1.2 in a phosphorylation-dependent manner to promote enhanced trafficking/recycling, clustering, and activity during β-adrenergic stimulation. We also report that a two-week treatment to restore youthful Bridging Integrator 1 (BIN1) levels in the hearts of 24-month-old mice rejuvenates cardiac function and substantially reverses the dysregulated endosomal recycling and disrupted CaV1.2 trafficking phenotype found in aging. These results increase our understanding of CaV1.2 regulation and provide a foundation for future work establishing a complete model of CaV1.2 trafficking.