# Decoding the enigma of cardiac amplification

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA AT DAVIS · 2020 · $594,007

## Abstract

Abstract
 The established “sliding-filament theory” of muscle contraction, while it is adequate to explain actin-myosin
force generation, does not suffice to account for changes in membrane lipid bilayer parallel to the sliding
filament during sarcomere shortening. To reconcile this unexplained phenomenon, our group has spent the last
decade trying to contend with this dilemma and have recently identified a mechanical amplifier, a non-
conventional motor protein, prestin (Slc26a5) and its oligomer Slc26a6 in cardiac myocytes, serving as a
muscle amplifier. Prestin is a member of the solute carrier (SLC) gene family. We hypothesize that prestin acts
as a “spring” to amplify actin-myosin force generation and accounts for the non-linear properties of muscle
contraction. Specifically, we hypothesize that prestin is expressed in cardiac myocytes and serves as a non-
conventional motor. Prestin is distinct in SLC26 family of proteins because of its molecular motor function in
contrast to the anion transport functions of other members. We further hypothesize that Slc26a6 is required as
an efficient transporter to create intracellular Cl- microdomain for the proper function of prestin. Using direct
electrophysiological measurements, we demonstrate that prestin is indeed, a weak anion transporter compared
with Slc26a6. To function effectively, prestin requires a strong anion exchanger for its optimal function. Thus,
we hypothesize that prestin requires a “team player”, Slc26a6, to form heteromeric proteins to perform distinct
functions in cardiac myocytes. Collectively, our findings greatly challenge the current paradigm in the field and
would not have been realized except for a close collaboration among seemingly disparate disciplines in
neuroscience, cardiovascular, and biomedical engineering investigative units.
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## Key facts

- **NIH application ID:** 9902512
- **Project number:** 5R01HL137228-04
- **Recipient organization:** UNIVERSITY OF CALIFORNIA AT DAVIS
- **Principal Investigator:** Nipavan Chiamvimonvat
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $594,007
- **Award type:** 5
- **Project period:** 2017-04-01 → 2023-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9902512

## Citation

> US National Institutes of Health, RePORTER application 9902512, Decoding the enigma of cardiac amplification (5R01HL137228-04). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/9902512. Licensed CC0.

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