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Published on: July 16, 2013
Evidence that heart connexin43 is a phosphoprotein
A F Lau1, V Hatch-Pigott, D S Crow
1Cancer Research Center, University of Hawaii, Honolulu 96813.
Journal of Molecular and Cellular Cardiology
|June 1, 1991
Summary
Cardiac gap junctions, formed by connexin43, facilitate heart cell communication. This study shows connexin43 is stoichiometrically phosphorylated in vivo, primarily on serine, impacting cardiac electrical signaling.
Area of Science:
- Cardiology
- Cell Biology
- Molecular Biology
Background:
- Cardiac gap junctions are crucial for myocardial electrical impulse conduction and synchronous contraction.
- These junctions are formed by connexin molecules, creating channels for intercellular ion exchange.
- Regulation of intercellular communication via gap junctions may involve phosphorylation.
Purpose of the Study:
- To provide direct evidence for in vivo phosphorylation of the heart gap junction protein, connexin43.
- To investigate the stoichiometry and sites of connexin43 phosphorylation in unstimulated heart tissues and cultured myocytes.
Main Methods:
- Analysis of unstimulated heart tissues and cultured myocytes.
- Investigation of connexin43-related proteins (45 and 47 kDa) phosphorylation.
- Identification of phosphorylated amino acid residues (serine and threonine).
Main Results:
- Connexin43 from unstimulated heart tissues and cultured myocytes is stoichiometrically phosphorylated in vivo.
- Phosphorylation of connexin43-related proteins (45 and 47 kDa) occurs predominantly on serine residues.
- A low level of phosphothreonine was detected in the 47 kDa connexin43-related protein.
Conclusions:
- Connexin43 phosphorylation is a significant in vivo modification in heart cells.
- Serine phosphorylation is the primary modification site for connexin43.
- These findings contribute to understanding the regulation of cardiac gap junction function.
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