Intracellular cysteine 346 is essentially involved in regulating Panx1 channel activity.
Pannexins constitute a family of proteins exhibiting predominantly hemichannel activity. Pannexin channels have been suggested to participate in a wide spectrum of biological functions such as propagation of calcium waves, release of IL-1β, and responses to ischemic conditions. At present, the molecular mechanisms regulating pannexin hemichannel activity are essentially unknown. Because cysteines have been shown to constitute key elements in regulating hemichannel properties of the connexin-type we performed site-directed mutagenesis of intracellular cysteine residues of Panx1. Cysteine to serine exchange (Cys → Ser) at the C-terminal position amino acid 346 led to a constitutively leaky hemichannel and subsequently to cell death. Increased channel activity was demonstrated by dye uptake and electrophysiological profiling in injected Xenopus laevis oocytes and transfected N2A cells. Mutations of the remaining intracellular cysteines did not result in major changes of Panx1 channel properties. From these data we conclude that the Cys-346 residue is important for proper functioning of the Panx1 channel.
Bunse
Stefanie
S
Department of Neuroanatomy and Molecular Brain Research, Ruhr-University Bochum, 44780 Bochum, Germany.
Schmidt
Matthias
M
Prochnow
Nora
N
Zoidl
Georg
G
Dermietzel
Rolf
R
D019943:Amino Acid Substitution; D000818:Animals; D017630:Connexins / Q000235:genetics / Q000378:metabolism*; D003545:Cysteine / Q000235:genetics / Q000378:metabolism*; D007473:Ion Channels / Q000235:genetics / Q000378:metabolism; D051379:Mice; D020125:Mutation, Missense; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009865:Oocytes / Q000166:cytology; D014982:Xenopus laevis
D017630:Connexins; D007473:Ion Channels; D009419:Nerve Tissue Proteins; C503631:Panx1 protein, mouse; D003545:Cysteine