# PROTEIN PHOSPHORYLATION IN SMOOTH MUSCLE

> **NIH NIH R01** · UNIVERSITY OF ILLINOIS AT CHICAGO · 1991 · $107,283

## Abstract

A comprehsensive study will be undertaken for studying myofilament
protein phosphorylation in smooth muscle to understand its role in
regulation of contractility.  Specifically:  1) Determination of the
amino acid sequence around the phosphorylation sites of the 20,000-
dalton myosin light chain (LC) isoforms in smooth muscles which are
contracting and relaxing under various conditions to correlate chemical
anatomy with physiological role; 2) Quantitation of phosphorylation of
LC isoforms in smooth muscles with different shortening velocity and
tension to delineate the parameters that relate phosphorylation of KC
isoforms to muscle contraction; 3) We will test the hypothesis that the
initial phase of smooth muscle contraction is regulated by LC
phosphorylation through protein kinase C.  The alternative hypothesis
will also be tested that the sustained phase of smooth muscle
contraction is regulated by the thin filament proteins with special
emphasis on caldesmon, the calmodulin binding protein; 4) Protein
phosphorylation will be compared between arteries and veins under
various conditions as well as between uteri from pregnant and
nonpregnant rats; 5) the significance of protein phosphorylation will be
further tested in muscles:  a) with reduced ATP content, b) treated with
phorbol esters, c) treated with okadaic acid; 6) The distinct
phosphorylation sites of KC will be characterized with specific
phosphoprotein phophatases.

These experiments require 32p-labeling of the muscles so that changes in
the [32p]phosphate content of a protein, as the result of a
physiological stimulus, may be followed at the level of microgram
protein quantities.  The correlation of biochemical data with the
physiological data is based on freezing the muscles at various stages of
the contraction-relaxation cycle.  The radioactive phosphorylated
proteins are isolated by two-dimensional gel electrophoresis, dissected
from the gels, and their [32p]phosphate content is determined by
counting.  The isolated proteins will also be subjected to phosphoamino
acid analysis and phosphopeptide mapping.

The knowledge gained from basic study on normal blood vessels could be
applied to the characterization of diseased conditions of blood vessels.
Studies on phosphorylation in normal uterus may form the basis for
understanding the disorders of uterus.

## Key facts

- **NIH application ID:** 3156876
- **Project number:** 5R01AR034602-17
- **Recipient organization:** UNIVERSITY OF ILLINOIS AT CHICAGO
- **SAM.gov UEI:** W8XEAJDKMXH3
- **Principal Investigator:** MICHAEL BARANY
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1991
- **Award amount:** $107,283
- **Award type:** 5
- **Project period:** 1984-09-01 → 1994-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3156876

## Citation

> US National Institutes of Health, RePORTER application 3156876, PROTEIN PHOSPHORYLATION IN SMOOTH MUSCLE (5R01AR034602-17). Retrieved via MORVS 2026-10-24 from https://api.morvs.ai/grant/nih/3156876. Licensed CC0.

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