# PATHWAYS IN CALCIUM REGULATION OF MUSCLE CONTRACTION

> **NIH NIH R01** · OKLAHOMA STATE UNIVERSITY STILLWATER · 1990 · $49,572

## Abstract

The goals of the proposed research are to understand the sequential states
in calcium activation of muscle contraction leading to the biochemical and
mechanical activity of the myofilaments and to know whether, how, and when
this process is modified physiologically by the interaction of cross-
bridges with the thin filament.  Experiments relating to regulation are
aimed at determining whether calcium binding to the regulatory protein TnC
of skinned muscle fibers in influenced by cross-bridges, and the state of
the cross-bridge leading to a further interaction between calcium and
cross-bridges.  Additionally, experiments are aimed at determining whether
cross-bridge activation through calcium binding to the regulatory sites is
affected by calcium binding to the calcium-magnesium sites of TnC.  In the
case of studies on TnI, the aims are to determine whether the interaction
between TnC and TnI differs when calcium is bound to TnC activating sites,
cross-bridges are bound to actin, and when both calcium and cross-bridges
are bound.  Experiments relating to the flexibility of the thin filament
are aimed at determining whether these motions play a regulatory role
through the binding of calcium to the activating sites leading to a
structural change in the thin filament or increased flexibility.  Studies
toward accomplishing these objectives will involve a careful but sensitive
approach using the information present in the emitted fluorescence from
labeled regulatory proteins incorporated into a physiological relevant
system, skinned-single skeletal muscle fibers.  The approach involves
monitoring the fluorescence using a micro-spectrofluorimeter to follow
absorption and emission spectra, excited stage lifetimes, and fluorescence
polarization anisotropy as a means of evaluating the processes influencing
the fluorescent emission.  That the skinned muscle fiber preparation is
capable of generating tension, provides additional and important
correlations of the fluorescent properties with such physiological
parameters as tension, stiffness, and shortening.  Methods also include the
use of ATP analogs and other compounds as a means of estimating the
influence of different cross-bridge states on the regulatory proteins.  The
proposed experiments bear directly on current views of calcium activation
mechanisms, and ultimately the understanding of basic muscle contractile
mechanisms.  That either cardiac or skeletal muscle performance, whether by
disease or under drug action, often involve modification of calcium
sensitivity of regulation further justifies the examination of feedback
relations between cross-bridge formation and activation of the thin
filament by calcium.

## Key facts

- **NIH application ID:** 3159944
- **Project number:** 5R01AR039728-02
- **Recipient organization:** OKLAHOMA STATE UNIVERSITY STILLWATER
- **SAM.gov UEI:** NNYDFK5FTSX9
- **Principal Investigator:** LAWRENCE D YATES
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1990
- **Award amount:** $49,572
- **Award type:** 5
- **Project period:** 1988-12-01 → 1991-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3159944

## Citation

> US National Institutes of Health, RePORTER application 3159944, PATHWAYS IN CALCIUM REGULATION OF MUSCLE CONTRACTION (5R01AR039728-02). Retrieved via MORVS 2026-10-24 from https://api.morvs.ai/grant/nih/3159944. Licensed CC0.

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