Seunghoon Oh

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The relationship between the loss of connexin 32 function and clinical manifestations of X-linked Charcot-Marie-Tooth (CMTX) disease is unknown. Here, we report that eight of nine CMTX mutations investigated form channels with measurable electrical conductance. Single-channel studies of two mutations demonstrate reduced junctional permeability caused by a(More)
Gap junctions are intercellular channels formed by the serial, head to head arrangement of two hemichannels. Each hemichannel is an oligomer of six protein subunits, which in vertebrates are encoded by the connexin gene family. All intercellular channels formed by connexins are sensitive to the relative difference in the membrane potential between coupled(More)
The fully open state of heterotypic gap junction channels formed by pairing cells expressing connexin 32 (Cx32) with those expressing connexin 26 (Cx26) rectifies in a way that cannot be predicted from the current-voltage (I-V) relation of either homotypic channel. Using a molecular genetic analysis, we demonstrate that charged amino acids positioned in the(More)
Intercellular channels formed by connexins (gap junctions) are sensitive to the application of transjunctional voltage (V(j)), to which they gate by the separate actions of their serially arranged hemichannels (Harris, A. L., D. C. Spray, and M. V. L. Bennett. 1981. J. Gen. Physiol. 77:95-117). Single channel studies of both intercellular and conductive(More)
We have explored the role of a proline residue located at position 87 in the second transmembrane segment (TM2) of gap junctions in the mechanism of voltage-dependent gating of connexin32 (Cx32). Substitution of this proline (denoted Cx32P87) with residues G, A, or V affects channel function in a progressive manner consistent with the expectation that a(More)
There is good evidence supporting the view that the transjunctional voltage sensor (V(j)-sensor) of Cx32 and other Group 1 connexins is contained within a segment of the N-terminus that contributes to the formation of the channel pore. We have shown that the addition of negatively charged amino acid residues at several positions within the first 10 amino(More)
The connexins are a family of homologous integral membrane proteins that form channels that provide a low resistance pathway for the transmission of electrical signals and the diffusion of small ions and non-electrolytes between coupled cells. Individuals carrying mutations in the gene encoding connexin 32 (Cx32), a gap junction protein expressed in the(More)
Previous studies have shown that charge substitutions in the amino terminus of a chimeric connexin, Cx32*43E1, which forms unapposed hemichannels in Xenopus oocytes, can result in a threefold difference in unitary conductance and alter the direction and amount of open channel current rectification. Here, we determine the charge selectivity of Cx32*43E1(More)
Although B[a]P-induced apoptosis has been demonstrated in Hepa1c1c7 cells, the cellular signaling pathway(s) by which benzo[a]pyrene (B[a]P) elicits a cytotoxicity-mediated apoptogenic role remains to be elucidated. In this study, we showed that B[a]P induces apoptosis in a p53-mediated and caspase-3-dependent manner, which relates to the accumulation of(More)