%0 Journal Article %1 RN1266 %A Dietrich, P. %A Hedrich, R. %D 1994 %J Planta %K anion channels myOwn %N 2 %P 301-304 %T Interconversion of Fast and Slow Gating Modes of Gcac1, a Guard-Cell Anion Channel %U /brokenurl#<Go to ISI>://WOS:A1994PY37700017 %V 195 %X For guard-cell protoplasts of Vicia faba L. we elucidated whether the slow (S-type) and rapid (R-type) activating anion channels represent different gating modes of GCAC1, the Guard Cell Anion Channel. in the whole-cell configuration of the patch-clamp technique, GCAC1 was activated in a Ca2+- and nucleotide-dependent manner. Cell-free outside-out membrane patches were isolated to determine the relative contribution of different gating modes or channel types to the overall anion current in this cell type. Within 2-15 min after the loss of cytoplasmic control through patch excision, depolarization-activated 38-pS channels characterized by flickering openings in the millisecond range convert into a channel of similar conductance but prolonged open times (hundreds of milliseconds) and lack of pronounced voltage-dependence. The rapid (R-type) and slow (S-type) gating modes exhibited similar ion selectivity but different susceptibility towards block by the stilbene derivative DNDS (4,4'-dinitrostilbene-2,2'-disulfonic acid). On R-type channels DNDS caused a flickering block and a shift in the threshold potential of activation whereas S-type channels remained unaffected. Because of the striking similarities of both channels with respect to single-channel conductance and relative permeability sequence on the one hand, but time-dependent conversion of R- into S-type gating after patch-excision on the other, we conclude that the mode of action of GCAC1 is under the control of cytoplasmic factors.

@article{RN1266, abstract = {For guard-cell protoplasts of Vicia faba L. we elucidated whether the slow (S-type) and rapid (R-type) activating anion channels represent different gating modes of GCAC1, the Guard Cell Anion Channel. in the whole-cell configuration of the patch-clamp technique, GCAC1 was activated in a Ca2+- and nucleotide-dependent manner. Cell-free outside-out membrane patches were isolated to determine the relative contribution of different gating modes or channel types to the overall anion current in this cell type. Within 2-15 min after the loss of cytoplasmic control through patch excision, depolarization-activated 38-pS channels characterized by flickering openings in the millisecond range convert into a channel of similar conductance but prolonged open times (hundreds of milliseconds) and lack of pronounced voltage-dependence. The rapid (R-type) and slow (S-type) gating modes exhibited similar ion selectivity but different susceptibility towards block by the stilbene derivative DNDS (4,4'-dinitrostilbene-2,2'-disulfonic acid). On R-type channels DNDS caused a flickering block and a shift in the threshold potential of activation whereas S-type channels remained unaffected. Because of the striking similarities of both channels with respect to single-channel conductance and relative permeability sequence on the one hand, but time-dependent conversion of R- into S-type gating after patch-excision on the other, we conclude that the mode of action of GCAC1 is under the control of cytoplasmic factors.}, added-at = {2024-02-14T14:38:32.000+0100}, author = {Dietrich, P. and Hedrich, R.}, biburl = {https://www.bibsonomy.org/bibtex/2b333a7f0ad6086257941546e0f40e8ad/rainerhedrich_2}, interhash = {031d847a28c96b131d6dc28e24300401}, intrahash = {b333a7f0ad6086257941546e0f40e8ad}, issn = {0032-0935}, journal = {Planta}, keywords = {anion channels myOwn}, note = {Py377 Times Cited:36 Cited References Count:16}, number = 2, pages = {301-304}, timestamp = {2024-02-14T14:38:32.000+0100}, title = {Interconversion of Fast and Slow Gating Modes of Gcac1, a Guard-Cell Anion Channel}, type = {Journal Article}, url = {/brokenurl#<Go to ISI>://WOS:A1994PY37700017}, volume = 195, year = 1994 }