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Intracellular calcium changes trigger connexin 32 hemichannel opening
Author(s) -
De Vuyst Elke,
Decrock Elke,
Cabooter Liesbet,
Dubyak George R,
Naus Christian C,
Evans W Howard,
Leybaert Luc
Publication year - 2006
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/sj.emboj.7600908
Subject(s) - library science , physiology , medicine , gerontology , computer science
Connexin hemichannels have been proposed as a diffusion pathway for the release of extracellular messengers like ATP and others, based on connexin expression models and inhibition by gap junction blockers. Hemichannels are opened by various experimental stimuli, but the physiological intracellular triggers are currently not known. We investigated the hypothesis that an increase of cytoplasmic calcium concentration ([Ca 2+ ] i ) triggers hemichannel opening, making use of peptides that are identical to a short amino‐acid sequence on the connexin subunit to specifically block hemichannels, but not gap junction channels. Our work performed on connexin 32 (Cx32)‐expressing cells showed that an increase in [Ca 2+ ] i triggers ATP release and dye uptake that is dependent on Cx32 expression, blocked by Cx32 (but not Cx43) mimetic peptides and a calmodulin antagonist, and critically dependent on [Ca 2+ ] i elevation within a window situated around 500 nM. Our results indicate that [Ca 2+ ] i elevation triggers hemichannel opening, and suggest that these channels are under physiological control.