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Human connexin40 gap junction channels are modulated by cAMP
H V van Rijen1, T A van Veen, M M Hermans
1Department of Medical Physiology and Sports Medicine, Faculty of Medicine, Utrecht University, The Netherlands. h.v.m.vanrijen@med.uu.nl
Cardiovascular Research
|March 23, 2000
Summary
Protein kinase A (PKA) phosphorylation increases the function of Connexin40 (Cx40) gap junctions. This finding is important for understanding intercellular communication in the heart and blood vessels.
Area of Science:
- Cellular biology
- Molecular biology
- Physiology
Background:
- Gap junctions facilitate direct electrical coupling between cells, crucial for homeostasis.
- Connexin40 (Cx40) forms gap junctions with restricted expression in the heart and vasculature.
Purpose of the Study:
- To investigate if protein-kinase-A (PKA)-mediated phosphorylation modulates Cx40 gap junction channels.
Main Methods:
- Stable transfection of a communication-deficient cell line with Cx40 cDNA.
- Analysis of Cx40 gap junction properties and cAMP modulation using immunocytochemistry, Western blotting, dual patch clamp, and dye coupling.
Main Results:
- cAMP treatment caused a mobility shift in Cx40 protein on Western blot.
- Macroscopic gap junctional conductance increased by 46.2% with cAMP.
- Single channel conductances shifted, and Lucifer Yellow permeability increased by 58%.
Conclusions:
- Cyclic AMP (cAMP) significantly enhances the conductance and permeability of Cx40 gap junctions.
- This modulation by cAMP may regulate intercellular communication in cardiac and vascular tissues.