This proposal outlines a comprehensive 5-year training program to develop Jared Kushner, MD, into an
independent translational investigator. Dr. Kushner is a general cardiologist and physician-scientist whose
ultimate goal is to improve care for patients with heart disease. To reach this goal, he is interested in
understanding how abnormal ion channel function in the heart can lead to cardiovascular disease and
conversely, how cardiovascular disease can cause maladaptive changes in ion channel regulation. In order to
become an independent translational scientist and leader in this field, Dr. Kushner has developed a career
development plan designed to fill specific educational and experiential gaps in his training. These short-term
goals include: 1) Receiving advanced training in cellular electrophysiology, with an emphasis on techniques
that probe ion channel function in their native milieu; 2) Acquiring experience in the analysis of large datasets,
with the goal of interpreting large-scale changes in gene and protein expression; 3) Developing expertise in
proteomics and the use of mass spectrometry; 4) Refining his current skills and developing new skills in
cardiovascular physiology, with emphasis on the experimental assessment of load-independent measures of
systolic and diastolic function; 5) Acquiring expertise in probing pathways of protein degradation, with
emphasis on the destruction of ion channels in health and disease; and 5) Developing skills critical to his long-
term success, with particular emphasis on his grant-writing skills. Columbia University, with its rich and
supportive research environment, proved to be an ideal setting for Dr. Kushner to organize a multi-disciplinary
mentorship team with the expertise to accomplish these goals.
In his proposed research project, Dr. Kushner will use results from proximity-labeling the interactome of the
L-type Ca2+ channel, CaV1.2, to gain insights into regulators of the channel essential to its function in normal
biology and in heart failure (HF), a condition characterized by reduced systolic function and adrenergic reserve,
often experienced by patients as increased shortness of breath with exertion. Using transgenic mice with
cardiac-specific expression of CaV1.2 subunits fused to the engineered ascorbate peroxidase, APEX2, he
probed the changing channel microenvironment in hearts of mice that developed chronic HF. He identified
significant changes in 71 of over 2000 proteins in the vicinity of CaV1.2 in HF. To determine if those proteins
perturb CaV1.2 function, he will analyze channel activity, contractility, and adrenergic responsiveness in genetic
knockouts of APEX-identified proteins. To measure effects on CaV1.2 expression, he will use a transgenic
mouse expressing a YFP-tagged a1C containing a bungarotoxin-binding site on an extracellular loop (BBS-
a1C). Treating isolated myocytes with fluorophore-conjugated bungarotoxin, he can track total and surface
expression of CaV1.2 with flow-cytometry. Generating HF in BBS-a1C mice crossed with knockouts of APEX-
identified proteins in HF, he can identify those neighboring proteins that alter CaV1.2 expression of HF.