# ISOLATED T-TUBULES AND TRIADS OF MUSCLE

> **NIH NIH R01** · UNIVERSITY OF MIAMI SCHOOL OF MEDICINE · 1989 · $174,394

## Abstract

The applicant previously has isolated transverse tubules and triads from
skeletal muscle and evaluated the biochemical and physiological properties
of the organelles.  The current proposal is directed towards a detailed
morphology, structure and biochemistry of the triadic junction region of
skeletal muscle.  The ultimate goal is to understand the mechanism of
excitation-contraction coupling.  The methods which will be employed will
be to extract, identify and isolate proteins from a preparation of intact
triads.  One protein has molecular weight 1.2 X one million and is
considered to be the spanning protein of the triad.  Monoclonal antibody
has been directed against this protein.  It will be employed to assist in
purifying the protein and to localize the protein by microscopy and
electron microscopy in muscle and other tissues.  The spanning protein will
be employed in cross linking experiments with triadic vesicles in order to
determine which proteins it interacts with in the triad.  The protein will
be examined by electron microscopy to determine its structure.

The identity of proteins which anchor the spanning protein to the membranes
of the T-tubule and terminal cisternae and the nature of the interaction of
calsequestrin with the triad will be elucidated.  This work will be carried
out employing cross linking agents and by extraction and isolation of
proteins.  Antibodies will be prepared and employed as described above.

We have identified a protein which promotes the formation of the triad
junction from T-tubules and terminal cisternae as glyceraldehyde phosphate
dehydrogenase.  This protein binds to calsequestrin.  We have recently
discovered that the enzyme is phosphorylated by ATP and that it promotes
the phosphorylation of triadic proteins.  The mechanism of this control of
protein phosphorylation will be investigated.  The goal is to determine how
the action is triggered physiologically, what the intermediates are, what
the kinetics of phosphorylation are and what the physiological consequences
are.  The role of phosphorylation in influencing Ca2+ accumulation and
release in sarcoplasmic reticulum and T-tubules will be evaluated.

## Key facts

- **NIH application ID:** 3155191
- **Project number:** 5R01AR021601-12
- **Recipient organization:** UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
- **SAM.gov UEI:** F8THLJQSAF93
- **Principal Investigator:** Anthony H Caswell
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1989
- **Award amount:** $174,394
- **Award type:** 5
- **Project period:** 1978-04-01 → 1991-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3155191

## Citation

> US National Institutes of Health, RePORTER application 3155191, ISOLATED T-TUBULES AND TRIADS OF MUSCLE (5R01AR021601-12). Retrieved via MORVS 2026-10-24 from https://api.morvs.ai/grant/nih/3155191. Licensed CC0.

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