title: Pannexins and gap junction protein diversity.
abstract: Gap junctions (GJs) are composed of proteins that form a channel connecting the cytoplasm of adjacent cells. Connexins were initially considered to be the only proteins capable of GJ formation. Another family of GJ proteins (innexins) were first found in invertebrates and were proposed to be renamed pannexins after their orthologs were discovered in vertebrates. The lack of both connexins and pannexins in the genomes of some metazoans suggests that other, still undiscovered GJ proteins exist. In vertebrates, connexins and pannexins co-exist. Here we discuss whether vertebrate pannexins have a nonredundant role in animal physiology. Pannexin channels appear to be suited for ATP and calcium signaling and play a role in the maintenance of calcium homeostasis by mechanisms implicating both GJ and nonjunctional function. Suggested roles in the ischemic death of neurons, schizophrenia, inflammation and tumor suppression have drawn much attention to exploring the molecular properties and cellular functions of pannexins.
authors.affiliation: Bascom Palmer Eye Institute,Department of Ophthalmology, University of Miami Miller School of Medicine, 1638 NW 10th Avenue, Miami, Florida 33136, USA. vshestopalov@med.miami.edu
authors.forename: V I
authors.initials: VI
authors.lastname: Shestopalov
authors.forename: Y
authors.initials: Y
authors.lastname: Panchin
mesh_terms: D000818:Animals; D020013:Calcium Signaling / Q000502:physiology; D002450:Cell Communication / Q000502:physiology; D017630:Connexins; D017629:Gap Junctions / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D009419:Nerve Tissue Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism; D009424:Nervous System Physiological Phenomena; D019899:Paracrine Communication / Q000502:physiology; D010802:Phylogeny; D013649:Taste / Q000502:physiology
chemical_list: D017630:Connexins; D009419:Nerve Tissue Proteins; C503631:Panx1 protein, mouse