alexa Inversion of both gating polarity and CO2 sensitivity of voltage gating with D3N mutation of Cx50.


Journal of Clinical & Experimental Ophthalmology

Author(s): Peracchia C, Peracchia LL

Abstract Share this page

Abstract The effect of CO(2)-induced acidification on transjunctional voltage (V(j)) gating was studied by dual voltage-clamp in oocytes expressing mouse connexin 50 (Cx50) or a Cx50 mutant (Cx50-D3N), in which the third residue, aspartate (D), was mutated to asparagine (N). This mutation inverted the gating polarity of Cx50 from positive to negative. CO(2) application greatly decreased the V(j) sensitivity of Cx50 channels, and increased that of Cx50-D3N channels. CO(2) also affected the kinetics of V(j) dependent inactivation of junctional current (I(j)), decreasing the gating speed of Cx50 channels and increasing that of Cx50-D3N channels. In addition, the D3N mutation increased the CO(2) sensitivity of chemical gating such that even CO(2) concentrations as low as 2.5\% significantly lowered junctional conductance (G(j)). With Cx50 channels G(j) dropped by 78\% with a drop in intracellular pH (pH(i)) to 6.83, whereas with Cx50-D3N channels G(j) dropped by 95\% with a drop in pH(i) to just 7.19. We have previously hypothesized that the way in which V(j) gating reacts to CO(2) might be related to connexin's gating polarity. This hypothesis is confirmed here by evidence that the D3N mutation inverts the gating polarity as well as the effect of CO(2) on V(j) gating sensitivity and speed. This article was published in Am J Physiol Cell Physiol and referenced in Journal of Clinical & Experimental Ophthalmology

Relevant Expert PPTs

Relevant Speaker PPTs

Recommended Conferences

Peer Reviewed Journals
Make the best use of Scientific Research and information from our 700 + peer reviewed, Open Access Journals
International Conferences 2017-18
Meet Inspiring Speakers and Experts at our 3000+ Global Annual Meetings

Contact Us

© 2008-2017 OMICS International - Open Access Publisher. Best viewed in Mozilla Firefox | Google Chrome | Above IE 7.0 version