Xenbase Image ID: 150380

Fig 2. Gating of GIRK1/2 by Gβγ.(A) Sources of Gβγ for GIRK activation. GαGDP●Gβγ is the undissociated G protein heterotrimer. Note that, in isolated Xenopus oocytes or HEK cells, in the absence of added agonist the right, GPCR-dependent branch of the reaction of Fig 2A does not significantly contribute to Ibasal, because there are no known Gαi/o-coupled GPCRs or ambient agonists that can "basally" activate the GTPase cycle (discussed in [51]). (B) The schemes of “concerted”, “graded contribution” and “separate gating transitions” models of channel activation. (C) Graded contribution of the four Gβγ-occupied GIRK states to Po. Fractional Po for each state was calculated by normalizing published Po values [13] of each of the four modes (corresponding to 1–4 Gβγ occupied state) to Po,max (corresponding to 4 Gβγ occupied channel). Almost identical values have been obtained from fractional activation ratios for engineered GIRK channels having 1 to 4 Gβγ binding sites [14]. Image published in: Yakubovich D et al. (2015) Image reproduced on Xenbase with permission of the publisher and the copyright holder. This image is reproduced with permission of the journal and the copyright holder. This is an open-access article distributed under the terms of the Creative Commons Attribution license Larger Image Printer Friendly View

Return to previous page