The applicant proposes a two aim strategy to explore molecular mechanisms of the regulation of ion-motive ATPases.
Aim 1 focuses on the cardiac calcium pump (SERCA) and its regulation by phospholamban (PLB). The proposed research will use fluorescence resonance energy transfer (FRET) and chemical crosslinking to test the hypothesis that PLB binds to multiple sites on SERCA, and that these discrete binding sites mediate different functional effects.
Aim 2 describes a novel high throughput assay for investigation of the binding interactions of phospholemman (PLM) with itself and its regulatory target, the sodium/potassium pump (NKA). The goal of the proposed experiments are to develop a novel peptide superinhibitor of NKA as a safer alternative to cardiac glycosides, a class of inotropic drugs used in the treatment of heart failure. The experiments described in the two Aims of this application will provide new insight into fundamental mechanisms of regulation of ion-motive ATPases, and may improve our understanding of the ion transport disorders associated with heart failure.

Public Health Relevance

This research project focuses on two enzymes that are critical for the function of the human heart. Both of these related enzymes are ion pumps;one transports calcium, and the other transports sodium. Ion pumps are of great clinical significance because of their central role in cardiac function and disease. Disorders of these proteins are associated with heart failure, a leading cause of human mortality, so they are considered high value therapeutic targets. The proposed experiments will reveal new information about the mechanisms that regulate the function of ion pumps. The knowledge gained in this research may yield new intervention strategies that will improve human health.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Research Project (R01)
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Biochemistry and Biophysics of Membranes Study Section (BBM)
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Krull, Holly
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Loyola University Chicago
Schools of Medicine
United States
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Makarewich, Catherine A; Munir, Amir Z; Schiattarella, Gabriele G et al. (2018) The DWORF micropeptide enhances contractility and prevents heart failure in a mouse model of dilated cardiomyopathy. Elife 7:
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