Levit NA , Sellitto C , Wang HZ , Li L , Srinivas M , Brink PR , White TW .

R01 AR059505 NIAMS NIH HHS , R01 AR59505 NIAMS NIH HHS , T32 GM008444 NIGMS NIH HHS

	Figure 2. Mefloquine (MFQ) and quinine derivatives (QUO) suppressed (a) Cx26-G45E and (b) -D50N hemichannel currents in Xenopus oocytesSingle cells held at −40mV were repeatedly pulsed with +50mV depolarizations (Vm) and membrane current (Im) was measured. Cells were exposed to 30µM inhibitor for 90sec by switching perfusion solutions after lmin (left, shown for mefloquine). Inhibitors were washed out for 2.5min, showing partial reversibility at the concentration tested. Summary data for inhibitors QU020, QU021, QU022, MFQ, and QU026 are shown as the mean residual instantaneous membrane current during 30µM drug application as a percentage of the pre-drug value (right). MFQ and QU026 produced the greatest inhibition of Cx26-G45E and -D50N membrane currents. Data are the means ± SD.
	Figure 3. Mefloquine (MFQ) attenuated KID-associated Cx26 hemichannel currents in a concentration-dependent and mutant-selective manner(a) Voltage-clamp recordings for three cells expressing Cx26-G45E showed an increasing magnitude of membrane current (Im) inhibition with 10, 30, and 100µM MFQ. (b) Mean MFQ response characteristics across Cx26-G45E-expressing cells showed that membrane current, plotted as a fraction of the starting value, fell by >25%, >50%, and >75% upon exposure to 10 (N=5), 30 (N=5), and l00µM (N=10) MFQ, respectively, (c) Effect of 10, 30, and 100µM MFQ perfusion on cells injected with Cx26-D50N, -A40V, -N14K, -G12R, -A88V, and -D50A. Bars represent the mean membrane current in the presence of the inhibitor as a percentage of the pre-drug value (n=5). Data are means ± SEM.
	Figure 4. Extracellular zinc (Zn++) reduced hemichannel currents mediated by KID-causing Cx26 mutations(a) Representative current (Im) traces corresponding to a single Cx26-G45E-expressing cell recorded in the presence of 0, 10, and 100µM Zn++. An h2O-injected control cell is shown for comparison, (b) Mean currents plotted against membrane potential (Vm) illustrated current-voltage relationships. Control cells showed negligible current (N=10). Whole-cell currents observed in Cx26-G45E oocytes (N=16) were inhibited by addition of 1 (N=5), 10 (N=5), and 100µM (N=5) Zn++ to the medium, (c) Concentration dependent effects of zinc perfusion in cells expressing Cx26-G45E, -D50N, -A40V, -N14K, -G12R, -A88V, and -D50A. Bars represent the mean current as a percentage of the pre-drug value for five cells. Data are means ± SEM.
	Figure 5. Mefloquine inhibited hemichannel activity in transgenic Cx26-G45E primary keratinocytes(a–b) Cx26-G45E mice recapitulate the epidermal pathology of KID syndrome using inducible tissue-specific expression of Cx26-G45E and eGFP in a hairless background, (c) In vivo fluorescence imaging demonstrated spatial correlation of fluorescence with skin lesions, (d) Keratinocytes isolated from Cx26-G45E lesions retained eGFP expression, facilitating their identification for patch-clamp electrophysiology (bar, 10µm). (e) Whole-cell membrane currents (Im) were recorded by patch-clamp electrophysiology. Nominal currents were observed in control keratinocytes. (f) Current density plotted against membrane potential (Vm) showed large macroscopic currents were elicited from Cx26-G45E cells (N=9) that were diminished by the addition of 100µM mefloquine (N=9) to levels resembling control cells (N=5). Data are means ± SEM.

Barrio, Gap junctions formed by connexins 26 and 32 alone and in combination are differently affected by applied voltage. 1991, Pubmed, Xenbase

Barrio, Gap junctions formed by connexins 26 and 32 alone and in combination are differently affected by applied voltage. 1991, Pubmed , Xenbase
Bruzzone, Connexin 43 hemi channels mediate Ca2+-regulated transmembrane NAD+ fluxes in intact cells. 2001, Pubmed
Bruzzone, Connections with connexins: the molecular basis of direct intercellular signaling. 1996, Pubmed
Bruzzone, Connexin40, a component of gap junctions in vascular endothelium, is restricted in its ability to interact with other connexins. 1993, Pubmed , Xenbase
Bruzzone, The double life of connexin channels: single is a treat. 2015, Pubmed
Bukauskas, Two distinct gating mechanisms in gap junction channels: CO2-sensitive and voltage-sensitive. 1997, Pubmed
Cotrina, Connexins regulate calcium signaling by controlling ATP release. 1998, Pubmed
Cruikshank, Potent block of Cx36 and Cx50 gap junction channels by mefloquine. 2004, Pubmed
DeVries, Hemi-gap-junction channels in solitary horizontal cells of the catfish retina. 1992, Pubmed
Donnelly, Differential susceptibility of Cx26 mutations associated with epidermal dysplasias to peptidoglycan derived from Staphylococcus aureus and Staphylococcus epidermidis. 2012, Pubmed
Ebihara, Properties of a nonjunctional current expressed from a rat connexin46 cDNA in Xenopus oocytes. 1993, Pubmed , Xenbase
Gerido, Aberrant hemichannel properties of Cx26 mutations causing skin disease and deafness. 2007, Pubmed , Xenbase
González, Species specificity of mammalian connexin-26 to form open voltage-gated hemichannels. 2006, Pubmed , Xenbase
Goodenough, Gap junctions. 2009, Pubmed
Gribble, The antimalarial agent mefloquine inhibits ATP-sensitive K-channels. 2000, Pubmed , Xenbase
Griffith, Cochleosaccular dysplasia associated with a connexin 26 mutation in keratitis-ichthyosis-deafness syndrome. 2006, Pubmed
Haruna, Severe form of keratitis-ichthyosis-deafness (KID) syndrome associated with septic complications. 2010, Pubmed
Horton, Gene splicing by overlap extension: tailor-made genes using the polymerase chain reaction. 1990, Pubmed
Jamsheer, Three novel GJA1 missense substitutions resulting in oculo-dento-digital dysplasia (ODDD) - further extension of the mutational spectrum. 2014, Pubmed
Janecke, GJB2 mutations in keratitis-ichthyosis-deafness syndrome including its fatal form. 2005, Pubmed
Jiang, Hemichannels formed by connexin 43 play an important role in the release of prostaglandin E(2) by osteocytes in response to mechanical strain. 2003, Pubmed
Jonard, A familial case of Keratitis-Ichthyosis-Deafness (KID) syndrome with the GJB2 mutation G45E. 2008, Pubmed
Kang, Interactions of the antimalarial drug mefloquine with the human cardiac potassium channels KvLQT1/minK and HERG. 2001, Pubmed
Kang, Connexin 43 hemichannels are permeable to ATP. 2008, Pubmed
Koppelhus, A novel mutation in the connexin 26 gene (GJB2) in a child with clinical and histological features of keratitis-ichthyosis-deafness (KID) syndrome. 2011, Pubmed
Kronengold, Pore-lining residues identified by single channel SCAM studies in Cx46 hemichannels. 2003, Pubmed , Xenbase
Kronengold, The N-terminal half of the connexin protein contains the core elements of the pore and voltage gates. 2012, Pubmed , Xenbase
Lee, Connexin mutations causing skin disease and deafness increase hemichannel activity and cell death when expressed in Xenopus oocytes. 2009, Pubmed , Xenbase
Li, Identification of gap junction blockers using automated fluorescence microscopy imaging. 2003, Pubmed
Lichti, Isolation and short-term culture of primary keratinocytes, hair follicle populations and dermal cells from newborn mice and keratinocytes from adult mice for in vitro analysis and for grafting to immunodeficient mice. 2008, Pubmed
Maeda, Structure of the connexin 26 gap junction channel at 3.5 A resolution. 2009, Pubmed
Maertens, Inhibition of volume-regulated and calcium-activated chloride channels by the antimalarial mefloquine. 2000, Pubmed
Malchow, Evidence for hemi-gap junctional channels in isolated horizontal cells of the skate retina. 1993, Pubmed
Mazereeuw-Hautier, Keratitis-ichthyosis-deafness syndrome: disease expression and spectrum of connexin 26 (GJB2) mutations in 14 patients. 2007, Pubmed
Mese, The Cx26-G45E mutation displays increased hemichannel activity in a mouse model of the lethal form of keratitis-ichthyosis-deafness syndrome. 2011, Pubmed
Mhaske, The human Cx26-D50A and Cx26-A88V mutations causing keratitis-ichthyosis-deafness syndrome display increased hemichannel activity. 2013, Pubmed , Xenbase
Montgomery, A novel connexin 26 gene mutation associated with features of the keratitis-ichthyosis-deafness syndrome and the follicular occlusion triad. 2004, Pubmed , Xenbase
Pfenniger, Mutations in connexin genes and disease. 2011, Pubmed
Picoli, Human connexin channel specificity of classical and new gap junction inhibitors. 2012, Pubmed
Richard, Missense mutations in GJB2 encoding connexin-26 cause the ectodermal dysplasia keratitis-ichthyosis-deafness syndrome. 2002, Pubmed
Richard, Functional defects of Cx26 resulting from a heterozygous missense mutation in a family with dominant deaf-mutism and palmoplantar keratoderma. 1998, Pubmed
Richard, Connexin disorders of the skin. 2005, Pubmed
Ripps, Properties of connexin26 hemichannels expressed in Xenopus oocytes. 2004, Pubmed , Xenbase
Rouan, trans-dominant inhibition of connexin-43 by mutant connexin-26: implications for dominant connexin disorders affecting epidermal differentiation. 2001, Pubmed , Xenbase
Rubinos, Mechanism of inhibition of connexin channels by the quinine derivative N-benzylquininium. 2012, Pubmed , Xenbase
Sbidian, Germline mosaicism in keratitis-ichthyosis-deafness syndrome: pre-natal diagnosis in a familial lethal form. 2010, Pubmed
Scott, Key functions for gap junctions in skin and hearing. 2011, Pubmed
Skinner, The keratitis, ichthyosis, and deafness (KID) syndrome. 1981, Pubmed
Srinivas, Quinine blocks specific gap junction channel subtypes. 2001, Pubmed
Srinivas, Closure of gap junction channels by arylaminobenzoates. 2003, Pubmed
Stong, A novel mechanism for connexin 26 mutation linked deafness: cell death caused by leaky gap junction hemichannels. 2006, Pubmed
Suadicani, P2X7 receptors mediate ATP release and amplification of astrocytic intercellular Ca2+ signaling. 2006, Pubmed
Sánchez, Differentially altered Ca2+ regulation and Ca2+ permeability in Cx26 hemichannels formed by the A40V and G45E mutations that cause keratitis ichthyosis deafness syndrome. 2010, Pubmed , Xenbase
Tang, Conformational changes in a pore-forming region underlie voltage-dependent "loop gating" of an unapposed connexin hemichannel. 2009, Pubmed , Xenbase
Traebert, Inhibition of hERG K+ currents by antimalarial drugs in stably transfected HEK293 cells. 2004, Pubmed
Turner, Expression of achaete-scute homolog 3 in Xenopus embryos converts ectodermal cells to a neural fate. 1994, Pubmed , Xenbase
Verselis, Opposite voltage gating polarities of two closely related connexins. 1994, Pubmed , Xenbase
Verselis, Divalent cations regulate connexin hemichannels by modulating intrinsic voltage-dependent gating. 2008, Pubmed , Xenbase
Verselis, Loop gating of connexin hemichannels involves movement of pore-lining residues in the first extracellular loop domain. 2009, Pubmed , Xenbase
Verselis, Connexin channel modulators and their mechanisms of action. 2013, Pubmed
Weingart, Long-chain n-alkanols and arachidonic acid interfere with the Vm-sensitive gating mechanism of gap junction channels. 1998, Pubmed
Wermuth, Selective optimization of side activities: another way for drug discovery. 2004, Pubmed
White, Functional analysis of human Cx26 mutations associated with deafness. 2000, Pubmed , Xenbase
White, Mouse Cx50, a functional member of the connexin family of gap junction proteins, is the lens fiber protein MP70. 1992, Pubmed , Xenbase
Ye, Functional hemichannels in astrocytes: a novel mechanism of glutamate release. 2003, Pubmed
Zhao, Gap junctions and cochlear homeostasis. 2006, Pubmed