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Biophys J
2004 Mar 01;863:1470-8. doi: 10.1016/S0006-3495(04)74215-0.
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Block by extracellular divalent cations of Drosophila big brain channels expressed in Xenopus oocytes.
Yanochko GM
,
Yool AJ
.
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Drosophila Big Brain (BIB) is a transmembrane protein encoded by the neurogenic gene big brain (bib), which is important for early development of the fly nervous system. BIB expressed in Xenopus oocytes is a monovalent cation channel modulated by tyrosine kinase signaling. Results here demonstrate that the BIB conductance shows voltage- and dose-dependent block by extracellular divalent cations Ca(2+) and Ba(2+) but not by Mg(2+) in wild-type channels. Site-directed mutagenesis of negatively charged glutamate (Glu(274)) and aspartate (Asp(253)) residues had no effect on divalent cation block. However, mutation of a conserved glutamate at position 71 (Glu(71)) in the first transmembrane domain (M1) altered channel properties. Mutation of Glu(71) to Asp introduced a new sensitivity to block by extracellular Mg(2+); substitutions with asparagine or glutamine decreased whole-cell conductance; and substitution with lysine compromised plasma membrane expression. Block by divalent cations is important in other ion channels for voltage-dependent function, enhanced signal resolution, and feedback regulation. Our data show that the wild-type BIB conductance is attenuated by external Ca(2+), suggesting that endogenous divalent cation block might be relevant for enhancing signal resolution or voltage dependence for the native signaling process in neuronal cell fate determination.
Anthony,
Cloned human aquaporin-1 is a cyclic GMP-gated ion channel.
2000, Pubmed,
Xenbase
Anthony,
Cloned human aquaporin-1 is a cyclic GMP-gated ion channel.
2000,
Pubmed
,
Xenbase
Doherty,
The Drosophila neurogenic gene big brain, which encodes a membrane-associated protein, acts cell autonomously and can act synergistically with Notch and Delta.
1997,
Pubmed
Fu,
Structure of a glycerol-conducting channel and the basis for its selectivity.
2000,
Pubmed
Goodman,
Embryonic development of identified neurones: differentiation from neuroblast to neurone.
1979,
Pubmed
Hazama,
Ion permeation of AQP6 water channel protein. Single channel recordings after Hg2+ activation.
2002,
Pubmed
,
Xenbase
Heginbotham,
A functional connection between the pores of distantly related ion channels as revealed by mutant K+ channels.
1992,
Pubmed
,
Xenbase
Kaupp,
Cyclic nucleotide-gated ion channels.
2002,
Pubmed
Lehmann,
On the phenotype and development of mutants of early neurogenesis inDrosophila melanogaster.
1983,
Pubmed
MacDonald,
Mechanisms of blockade of excitatory amino acid receptor channels.
1990,
Pubmed
Nichols,
Inward rectifier potassium channels.
1997,
Pubmed
Park,
Divalent cation selectivity in a cyclic nucleotide-gated ion channel.
1995,
Pubmed
,
Xenbase
Preston,
Appearance of water channels in Xenopus oocytes expressing red cell CHIP28 protein.
1992,
Pubmed
,
Xenbase
Rao,
The big brain gene of Drosophila functions to control the number of neuronal precursors in the peripheral nervous system.
1992,
Pubmed
Rao,
Similarity of the product of the Drosophila neurogenic gene big brain to transmembrane channel proteins.
1990,
Pubmed
Reizer,
The MIP family of integral membrane channel proteins: sequence comparisons, evolutionary relationships, reconstructed pathway of evolution, and proposed functional differentiation of the two repeated halves of the proteins.
1993,
Pubmed
Ren,
Visualization of a water-selective pore by electron crystallography in vitreous ice.
2001,
Pubmed
Stern,
Divalent cations directly affect the conductance of excised patches of rod photoreceptor membrane.
1987,
Pubmed
Sui,
Structural basis of water-specific transport through the AQP1 water channel.
,
Pubmed
Yanochko,
Regulated cationic channel function in Xenopus oocytes expressing Drosophila big brain.
2002,
Pubmed
,
Xenbase
Yasui,
Rapid gating and anion permeability of an intracellular aquaporin.
1999,
Pubmed
,
Xenbase
Yool,
Forskolin stimulation of water and cation permeability in aquaporin 1 water channels.
1996,
Pubmed
,
Xenbase
Yool,
New roles for old holes: ion channel function in aquaporin-1.
2002,
Pubmed
Zimmerman,
Cation interactions within the cyclic GMP-activated channel of retinal rods from the tiger salamander.
1992,
Pubmed
