S-nitrosylation and permeation through connexin 43 hemichannels in astrocytes: induction by oxidant stress and reversal by reducing agents.

ABSTRACT: Marked increase in cell permeability ascribed to open connexin (Cx)43 hemichannels is induced by metabolic inhibition (MI) of cortical astrocytes in culture, but the molecular mechanisms are not established. Dephosphorylation and/or oxidation of Cx43 hemichannels was proposed as a potential mechanism to increase their open probability. We now demonstrate that MI increases the number of hemichannels on the cell surface assayed by biotinylation and Western blot, and that this change is followed by increased dephosphorylation and S-nitrosylation. The increase in rate of dye uptake caused by MI is comparable to the increase in surface expression; thus, open probability and permeation per hemichannel may be unchanged. Reducing agents did not affect dephosphorylation of Cx43 hemichannels but red

SUBMITTER: Retamal MA 

PROVIDER: S-EPMC1450196 | biostudies-literature | 2006 Mar

REPOSITORIES: biostudies-literature