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https://hdl.handle.net/2440/34787
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dc.contributor.author | Yanochko, G. | - |
dc.contributor.author | Yool, A. | - |
dc.date.issued | 2004 | - |
dc.identifier.citation | Biophysical Journal, 2004; 86(3):1470-1478 | - |
dc.identifier.issn | 0006-3495 | - |
dc.identifier.issn | 1542-0086 | - |
dc.identifier.uri | http://hdl.handle.net/2440/34787 | - |
dc.description | Copyright © 2004 The Biophysical Society | - |
dc.description.abstract | 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 Ca2+ and Ba2+ but not by Mg2+ in wild-type channels. Site-directed mutagenesis of negatively charged glutamate (Glu274) and aspartate (Asp253) residues had no effect on divalent cation block. However, mutation of a conserved glutamate at position 71 (Glu71) in the first transmembrane domain (M1) altered channel properties. Mutation of Glu71 to Asp introduced a new sensitivity to block by extracellular Mg2+; 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 Ca2+, 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. | - |
dc.description.statementofresponsibility | Gina M. Yanochko and Andrea J. Yool | - |
dc.language.iso | en | - |
dc.publisher | Biophysical Society | - |
dc.source.uri | http://www.biophysj.org/cgi/content/abstract/86/3/1470 | - |
dc.subject | Oocytes | - |
dc.subject | Cells, Cultured | - |
dc.subject | Extracellular Fluid | - |
dc.subject | Animals | - |
dc.subject | Xenopus laevis | - |
dc.subject | Drosophila | - |
dc.subject | Cations, Divalent | - |
dc.subject | Barium | - |
dc.subject | Calcium | - |
dc.subject | Magnesium | - |
dc.subject | Ion Channels | - |
dc.subject | Drosophila Proteins | - |
dc.subject | Membrane Proteins | - |
dc.subject | Recombinant Proteins | - |
dc.subject | Mutagenesis, Site-Directed | - |
dc.subject | Ion Channel Gating | - |
dc.subject | Structure-Activity Relationship | - |
dc.subject | Membrane Potentials | - |
dc.title | Block by extracellular divalent cations of Drosophila big brain channels expressed in Xenopus oocytes | - |
dc.type | Journal article | - |
dc.identifier.doi | 10.1016/S0006-3495(04)74215-0 | - |
pubs.publication-status | Published | - |
dc.identifier.orcid | Yool, A. [0000-0003-1283-585X] | - |
Appears in Collections: | Aurora harvest Molecular and Biomedical Science publications |
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