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Protein phosphorylation and hydrogen ions modulate calcium-induced closure of gap junction channels

1990; Elsevier BV; Volume: 57; Issue: 2 Linguagem: Inglês

10.1016/s0006-3495(90)82537-6

1542-0086

Rogelio O. Arellano, Amelia Rivera, F. Ramón,

Nicotinic Acetylcholine Receptors Study

The regulation of the cell- to-cell pathway formed by gap junctions seems to involve the interaction of the junctional channels with either cal- cium or hydrogen ions, as well as protein phosphorylation and calmodulin.These mechanisms of junctional regulation have been considered to act independently on specific sites of the gap junction protein; however, the possibility that they may be interrelated has not been adequately explored mainly due to the difficulties involved in simul- taneous measurement of intracellular cations and protein phosphorylation.To further understanding of mecha- nisms regulating gap junctions, we have internally perfused coupled lateral axons from crayfish with solutions con- taining different calcium and hydrogen concentrations under conditions favor- ing phosphorylation, while monitoring the junctional conductance.We found that calcium ions regulate cell commu- nication probably through a direct inter- action with the channel protein.Phosphorylation and low pH do not alter junctional conductance themselves, but appear only to modulate the effects of calcium, possibly by altering the affinity of the channel for calcium.We propose that a combination of free intracellular calcium and protein phosphorylation form an important physiological mechanism regulating intercellular communication.