| Structural highlights
Function
IRK10_MAGMG Inward rectifier potassium channel that mediates potassium uptake into the cell. Inward rectifier potassium channels are characterized by a greater tendency to allow potassium to flow into the cell rather than out of it. The inward rectification may be achieved by the blockage of outward current by cytoplasmic divalent metal ions and polyamines. Complements an E.coli mutant that is defective in K(+) uptake.[1] [2] [3]
Publication Abstract from PubMed
KirBac channels are prokaryotic homologs of mammalian inwardly rectifying channels (Kir) and recent structures of KirBac3.1 have provided important insights into the structural basis of gating in Kir channels. In this study we demonstrate that KirBac3.1 channel activity is strongly pH-dependent, and used X-ray crystallography to determine the structural changes that arise from an activatory mutation (S205L) located in the cytoplasmic domain (CTD). This mutation stabilizes a novel energetically favorable open conformation where changes at the intersubunit interface in the CTD also alter the electrostatic potential of the inner cytoplasmic cavity. These results provide a structural explanation for the activatory effect of this mutation and provide a greater insight into the role of the CTD in Kir channel gating.
Control of KirBac3.1 potassium channel gating at the interface between cytoplasmic domains.,Zubcevic L, Bavro VN, Muniz JR, Schmidt MR, Wang S, De Zorzi R, Venien-Bryan C, Sansom MS, Nichols CG, Tucker SJ J Biol Chem. 2013 Nov 20. PMID:24257749[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Paynter JJ, Andres-Enguix I, Fowler PW, Tottey S, Cheng W, Enkvetchakul D, Bavro VN, Kusakabe Y, Sansom MS, Robinson NJ, Nichols CG, Tucker SJ. Functional complementation and genetic deletion studies of KirBac channels: activatory mutations highlight gating-sensitive domains. J Biol Chem. 2010 Dec 24;285(52):40754-61. doi: 10.1074/jbc.M110.175687. Epub, 2010 Sep 28. PMID:20876570 doi:http://dx.doi.org/10.1074/jbc.M110.175687
- ↑ Clarke OB, Caputo AT, Hill AP, Vandenberg JI, Smith BJ, Gulbis JM. Domain reorientation and rotation of an intracellular assembly regulate conduction in Kir potassium channels. Cell. 2010 Jun 11;141(6):1018-29. PMID:20564790
- ↑ Bavro VN, De Zorzi R, Schmidt MR, Muniz JR, Zubcevic L, Sansom MS, Venien-Bryan C, Tucker SJ. Structure of a KirBac potassium channel with an open bundle crossing indicates a mechanism of channel gating. Nat Struct Mol Biol. 2012 Jan 8;19(2):158-63. doi: 10.1038/nsmb.2208. PMID:22231399 doi:10.1038/nsmb.2208
- ↑ Zubcevic L, Bavro VN, Muniz JR, Schmidt MR, Wang S, De Zorzi R, Venien-Bryan C, Sansom MS, Nichols CG, Tucker SJ. Control of KirBac3.1 potassium channel gating at the interface between cytoplasmic domains. J Biol Chem. 2013 Nov 20. PMID:24257749 doi:http://dx.doi.org/10.1074/jbc.M113.501833
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