Bichet D et al. (2004), Evolving potassium channels by means of yeast s...

XB-ART-3724

Proc Natl Acad Sci U S A 2004 Mar 30;10113:4441-6. doi: 10.1073/pnas.0401195101.

Show Gene links Show Anatomy links

Evolving potassium channels by means of yeast selection reveals structural elements important for selectivity.

Bichet D , Lin YF , Ibarra CA , Huang CS , Yi BA , Jan YN , Jan LY .

???displayArticle.abstract???
Potassium channels are widely distributed. To serve their physiological functions, such as neuronal signaling, control of insulin release, and regulation of heart rate and blood flow, it is essential that K+ channels allow K+ but not the smaller and more abundant Na+ ions to go through. The narrowest part of the channel pore, the selectivity filter formed by backbone carbonyls of the GYG-containing K+ channel signature sequence, approximates the hydration shell of K+ ions. However, the K+ channel signature sequence is not sufficient for K+ selectivity. To identify structural elements important for K+ selectivity, we randomly mutagenized the G protein-coupled inwardly rectifying potassium channel 3.2 (GIRK2) bearing the S177W mutation on the second transmembrane segment. This mutation confers constitutive channel activity but abolishes K+ selectivity and hence the channel's ability to complement the K+ transport deficiency of Deltatrk1Deltatrk2 mutant yeast. S177W-containing GIRK2 mutants that support yeast growth in low-K+ medium contain multiple suppressors, each partially restoring K+ selectivity to S177W-containing double mutants. These suppressors include mutations in the first transmembrane segment and the pore helix, likely exerting long-range actions to restore K+ selectivity, as well as a mutation of a second transmembrane segment residue facing the cytoplasmic half of the pore, below the selectivity filter. Some of these suppressors also affected channel gating (channel open time and opening frequency determined in single-channel analyses), revealing intriguing interplay between ion permeation and channel gating.

???displayArticle.pubmedLink??? 15070737
???displayArticle.pmcLink??? PMC384766
???displayArticle.link??? Proc Natl Acad Sci U S A
???displayArticle.grants??? [+]

Species referenced: Xenopus
Genes referenced: ins kcnj6

References [+] :

Abrams, The role of a single aspartate residue in ionic selectivity and block of a murine inward rectifier K+ channel Kir2.1. 1996, Pubmed

Abrams, The role of a single aspartate residue in ionic selectivity and block of a murine inward rectifier K+ channel Kir2.1. 1996, Pubmed
Alagem, The pore helix is involved in stabilizing the open state of inwardly rectifying K+ channels. 2003, Pubmed , Xenbase
Aqvist, Ion permeation mechanism of the potassium channel. 2000, Pubmed
Bernèche, Energetics of ion conduction through the K+ channel. 2001, Pubmed
Bichet, Merging functional studies with structures of inward-rectifier K(+) channels. 2003, Pubmed
Choe, Permeation and gating of an inwardly rectifying potassium channel. Evidence for a variable energy well. 1998, Pubmed , Xenbase
Dart, The selectivity filter of a potassium channel, murine kir2.1, investigated using scanning cysteine mutagenesis. 1998, Pubmed
Doyle, The structure of the potassium channel: molecular basis of K+ conduction and selectivity. 1998, Pubmed
Fakler, A structural determinant of differential sensitivity of cloned inward rectifier K+ channels to intracellular spermine. 1994, Pubmed , Xenbase
Fujiwara, Ser165 in the second transmembrane region of the Kir2.1 channel determines its susceptibility to blockade by intracellular Mg2+. 2002, Pubmed , Xenbase
Heginbotham, Mutations in the K+ channel signature sequence. 1994, Pubmed , Xenbase
Ho, Molecular mechanism for sodium-dependent activation of G protein-gated K+ channels. 1999, Pubmed , Xenbase
Jin, A novel high-affinity inhibitor for inward-rectifier K+ channels. 1998, Pubmed , Xenbase
Kofuji, Functional analysis of the weaver mutant GIRK2 K+ channel and rescue of weaver granule cells. 1996, Pubmed , Xenbase
Korn, Statistical discrimination of fractal and Markov models of single-channel gating. 1988, Pubmed
Kuo, Crystal structure of the potassium channel KirBac1.1 in the closed state. 2003, Pubmed
Lesage, Cloning provides evidence for a family of inward rectifier and G-protein coupled K+ channels in the brain. 1994, Pubmed , Xenbase
Liman, Subunit stoichiometry of a mammalian K+ channel determined by construction of multimeric cDNAs. 1992, Pubmed , Xenbase
Lu, Permeant ion-dependent changes in gating of Kir2.1 inward rectifier potassium channels. 2001, Pubmed , Xenbase
Lu, Electrostatic tuning of Mg2+ affinity in an inward-rectifier K+ channel. 1994, Pubmed , Xenbase
Lu, Probing ion permeation and gating in a K+ channel with backbone mutations in the selectivity filter. 2001, Pubmed , Xenbase
McManus, Kinetic states and modes of single large-conductance calcium-activated potassium channels in cultured rat skeletal muscle. 1988, Pubmed
Miller, Enzyme specificity under dynamic control: a normal mode analysis of alpha-lytic protease. 1999, Pubmed
Minor, Transmembrane structure of an inwardly rectifying potassium channel. 1999, Pubmed
Morais-Cabral, Energetic optimization of ion conduction rate by the K+ selectivity filter. 2001, Pubmed
Navarro, Nonselective and G betagamma-insensitive weaver K+ channels. 1996, Pubmed
Nimigean, Na+ block and permeation in a K+ channel of known structure. 2002, Pubmed
Nishida, Structural basis of inward rectification: cytoplasmic pore of the G protein-gated inward rectifier GIRK1 at 1.8 A resolution. 2002, Pubmed
Petit-Jacques, Synergistic activation of G protein-gated inwardly rectifying potassium channels by the betagamma subunits of G proteins and Na(+) and Mg(2+) ions. 1999, Pubmed , Xenbase
Reuveny, Contributions of a negatively charged residue in the hydrophobic domain of the IRK1 inwardly rectifying K+ channel to K(+)-selective permeation. 1996, Pubmed , Xenbase
Roncaglia, Pore topology of the hyperpolarization-activated cyclic nucleotide-gated channel from sea urchin sperm. 2002, Pubmed , Xenbase
Sadja, Coupling Gbetagamma-dependent activation to channel opening via pore elements in inwardly rectifying potassium channels. 2001, Pubmed , Xenbase
Shyng, Depletion of intracellular polyamines relieves inward rectification of potassium channels. 1996, Pubmed , Xenbase
Sigworth, Data transformations for improved display and fitting of single-channel dwell time histograms. 1987, Pubmed
Slesinger, Functional effects of the mouse weaver mutation on G protein-gated inwardly rectifying K+ channels. 1996, Pubmed , Xenbase
Stanfield, A single aspartate residue is involved in both intrinsic gating and blockage by Mg2+ of the inward rectifier, IRK1. 1994, Pubmed
Stanfield, Constitutively active and G-protein coupled inward rectifier K+ channels: Kir2.0 and Kir3.0. 2002, Pubmed
Stemmer, DNA shuffling by random fragmentation and reassembly: in vitro recombination for molecular evolution. 1994, Pubmed
Tong, The weaver mutation changes the ion selectivity of the affected inwardly rectifying potassium channel GIRK2. 1996, Pubmed , Xenbase
Tucker, Heteromeric channel formation and Ca(2+)-free media reduce the toxic effect of the weaver Kir 3.2 allele. 1996, Pubmed , Xenbase
Wible, Gating of inwardly rectifying K+ channels localized to a single negatively charged residue. 1994, Pubmed , Xenbase
Yang, Control of rectification and permeation by residues in two distinct domains in an inward rectifier K+ channel. 1995, Pubmed , Xenbase
Yi, Yeast screen for constitutively active mutant G protein-activated potassium channels. 2001, Pubmed , Xenbase
Zhou, Chemistry of ion coordination and hydration revealed by a K+ channel-Fab complex at 2.0 A resolution. 2001, Pubmed