title: Open pore block of connexin26 and connexin32 hemichannels by neutral, acidic and basic glycoconjugates.
abstract: The mechanisms of molecular discrimination by connexin channels are of acute biological and medical importance. The availability of affinity or open-pore blocking reagents for reliable and specific study of the connexin permeability pathway, would make possible the rigorous cellular and physiological studies required to inform, in molecular terms, the underlying role of intercellular communication pathways in development and disease. Previous work utilized a series of glucosaccharides labeled with an uncharged fluorescent aminopyridine (PA-) group to establish steric constraints to permeability through connexin hemichannels. In that work, the smallest probe permeable through homomeric Cx26 and heteromeric Cx26-Cx32 channels was the PA-disaccharide, and the smallest probe permeable through homomeric Cx32 channels was the PA-trisaccharide. The larger impermeable probes did not block permeation of the smaller probes. Building on this work, a new set of glucosaccharide probes was developed in which the label was one of a homologous series of novel anthranilic acid derivatives (ABG) that carry negative or positive formal charge or remain neutral at physiological pH. When the PA-label of the smallest impermeant PA-derivatized oligosaccharides was replaced by ABG label, the resulting probes acted as reversible, high-affinity inhibitors of large molecule permeation through connexin pores in a size and connexin-specific manner.
authors.affiliation: Department of Pharmacology and Physiology, New Jersey Medical School, Newark, NJ 07103, USA. lockeda@umdnj.edu
authors.forename: Darren
authors.initials: D
authors.lastname: Locke
authors.forename: Lai-Xi
authors.initials: LX
authors.lastname: Wang
authors.forename: Carville G
authors.initials: CG
authors.lastname: Bevans
authors.forename: Yuan C
authors.initials: YC
authors.lastname: Lee
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Harris
mesh_terms: D000818:Animals; D002463:Cell Membrane Permeability / Q000187:drug effects*; D000072259:Connexin 26; D017630:Connexins / Q000378:metabolism*; D005456:Fluorescent Dyes / Q000737:chemistry; D006001:Glycoconjugates / Q000494:pharmacology; D022781:Hepatocytes / Q000378:metabolism; D006801:Humans; D042361:Mammary Glands, Human / Q000378:metabolism; D062367:ortho-Aminobenzoates / Q000032:analysis / Q000494:pharmacology*; D000097002:Gap Junction beta-1 Protein
chemical_list: D000072259:Connexin 26; D017630:Connexins; D005456:Fluorescent Dyes; D006001:Glycoconjugates; D062367:ortho-Aminobenzoates; D000097002:Gap Junction beta-1 Protein; C000607042:GJB2 protein, human; C031385:anthranilic acid