title: Nature of plasmalemmal functional "hemichannels".
abstract: The molecular identity of the protein forming "hemichannels" at non-junctional membranes is disputed. The family of gap junction proteins, innexins, connexins, and pannexins share several common features, including permeability characteristics and sensitivity to blocking agents. Such overlap in properties renders the identification of which of these protein species actually establishes the non-junctional membrane conductance and permeability quite complicated, especially because in vertebrates pannexins and connexins have largely overlapping distributions in tissues. Recently, attempts to establish criteria to identify events that are "hemichannel" mediated and those to allow the distinction between connexin- from pannexin-mediated events have been proposed. Here, I present an update on that topic and discuss the most recent findings related to the nature of functional "hemichannels" focusing on connexin43 and pannexin1. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and characteristics.
authors.affiliation: Dominick P.Purpura Department of Neuroscience, Albert Einstein Collegeof Medicine, Bronx, NY, USA. eliana.scemes@einstein.yu.edu
authors.forename: Eliana
authors.initials: E
authors.lastname: Scemes
mesh_terms: D000818:Animals; D001703:Biophysics / Q000379:methods; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D002450:Cell Communication; D002462:Cell Membrane / Q000378:metabolism; D018031:Connexin 43 / Q000737:chemistry; D017630:Connexins / Q000737:chemistry; D017629:Gap Junctions; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D008954:Models, Biological; D009419:Nerve Tissue Proteins / Q000737:chemistry; D010539:Permeability; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry; D015398:Signal Transduction
chemical_list: D002352:Carrier Proteins; D018031:Connexin 43; D017630:Connexins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C492764:PANX1 protein, human; C486771:PLVAP protein, human; D011506:Proteins