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dc.contributor.advisorH. Robert Horvitz.en_US
dc.contributor.authorPerez de la Cruz, Ignacio, 1973-en_US
dc.contributor.otherMassachusetts Institute of Technology. Dept. of Biology.en_US
dc.date.accessioned2006-03-24T18:02:04Z
dc.date.available2006-03-24T18:02:04Z
dc.date.copyright2002en_US
dc.date.issued2002en_US
dc.identifier.urihttp://hdl.handle.net/1721.1/29908
dc.descriptionThesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Biology, 2002.en_US
dc.descriptionIncludes bibliographical references.en_US
dc.description.abstractK+ channels generate and tune the electrical signals that underlie the functioning of neurons and other excitable cells. We have studied a set of genetically-interacting genes, sup-9, sup-10 and unc-93, whose products are predicted to form a protein complex that when misregulated leads to severe muscle paralysis in the nematode C. elegans. We cloned sup-9 and found it encodes a K+ channel of the recently discovered mammalian two-pore family of voltage-insensitive leak channels, suggesting that SUP-10 and UNC-93, along with multiple UNC-93-like genes in Drosophila and humans, are the first regulatory subunits for two-pore K+ channels. Based on pharmacological data, we propose that gain-of-function mutations in the sup-9 channelor in its proposed subunits result in muscle paralysis through excessive K+ efflux and hyperpolarization of muscle cells. We cloned sup-18, a regulator of the channel complex, and show that SUP-18 is a type-three transmembrane protein that colocalizes with SUP-9 in muscle membranes and whose intracellular domain is similar to bacterial NADH nitroreductases that use an FMN cofactor. We identified a mutation in a predicted FMN-binding residue of SUP-18 that both eliminates its in vivo function without disrupting its membrane localization and that impairs the enzymatic activity of a related Thermophilus enzyme, suggesting that SUP-18 may couple cell metabolism with membrane excitability.en_US
dc.description.abstract(cont.) Through genetic and molecular studies, we determined that the SUP-10 subunit acts together with SUP-18 to activate the SUP-9 channel through a novel conserved domain in SUP-9. This domain is not required for the activation of SUP-9 by UNC-93, thus defining two independent modes of activation for a two-pore channel by multiple subunits. We also discovered a second domain in SUP-9, conserved in the human TASK-1 and TASK-3 channels, that integrates multiple regulatory inputs. Finally, our analysis of the subcellular localization of other C. elegans two-pore channels suggests that they can be differentially targeted within the cell membrane of muscle cells.en_US
dc.description.statementofresponsibilityby Ignacio Perez de la Cruz.en_US
dc.format.extent234 leavesen_US
dc.format.extent10184954 bytes
dc.format.extent10183807 bytes
dc.format.mimetypeapplication/pdf
dc.format.mimetypeapplication/pdf
dc.language.isoengen_US
dc.publisherMassachusetts Institute of Technologyen_US
dc.rightsM.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.en_US
dc.rights.urihttp://dspace.mit.edu/handle/1721.1/7582
dc.subjectBiology.en_US
dc.titleRegulation of a two-pore K+ channel by multiple subunits in Caenorhabditis elegansen_US
dc.typeThesisen_US
dc.description.degreePh.D.en_US
dc.contributor.departmentMassachusetts Institute of Technology. Dept. of Biology.en_US
dc.identifier.oclc51640229en_US


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