# MYOSIN ISOENYZMES AND CONTRACTION IN DEVELOPING MUSCLES

> **NIH NIH R01** · UNIVERSITY OF WISCONSIN-MADISON · 1990 · $140,389

## Abstract

Biochemical studies of mammalian skeletal muscle have found that the major
contractile protein myosin undergoes transitions in its subunit structure
during development from its embryonic to its adult forms.  We will
investigate the physiological function(s) of these various forms, or
isoenzymes, of myosin in rabbit and avian skeletal muscles.  This will be
done through the use of single muscle fiber preparations from which the
surface membranes have been removed, thereby allowing direct control of
muscle activation with Ca2+.  Measurements of tension, stiffness and
shortening velocity, as well as the tension transients in response to rapid
length changes, will be made in order to determine the mechanical
properties of the myosin cross-bridges and the kinetics of interaction of
myosin with actin.  These same measurements will also be made in living
single fibers obtained from muscles at different stages of development in
order to determine the extent to which developmental changes in mechanical
properties are due to changes in the contractile proteins per se.  The
myosin isoenzymes composition of these same skinned and living fiber
preparations will then be determined using SDS polyacrylamide gel
electrophoresis and high voltage iso-electric focusing procedures that have
been developed in our laboratory for use on a micro-scale.  These
mechanical and biochemical measurements will be done on muscles that are
destined to be fast and those that are destined to be slow in the adult and
will encompass the fetal, neonatal and adult stages of development.  Such
measurements made on the same skinned single fiber preparations will allow
straightforward conclusions regarding the possible relationships between
the myosin isoenzymes that are present and physiological function.  This
experimental approach will provide new and valuable information about the
molecular basis of the regulation of the interaction of myosin with actin
in preparations which retain the structural filamentary organization of
living muscle and should therefore further our understanding of muscle
contraction.

## Key facts

- **NIH application ID:** 3156102
- **Project number:** 5R01AR031806-08
- **Recipient organization:** UNIVERSITY OF WISCONSIN-MADISON
- **SAM.gov UEI:** LCLSJAGTNZQ7
- **Principal Investigator:** Richard L Moss
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1990
- **Award amount:** $140,389
- **Award type:** 5
- **Project period:** 1983-01-01 → 1991-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3156102

## Citation

> US National Institutes of Health, RePORTER application 3156102, MYOSIN ISOENYZMES AND CONTRACTION IN DEVELOPING MUSCLES (5R01AR031806-08). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3156102. Licensed CC0.

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