Localization of LvsA on the contractile vacuole in Dictyostelium discoideum

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dc.contributor.advisorDe Lozanne, Arturoen
dc.contributor.committeeMemberHuibregtse, Jonen
dc.contributor.committeeMemberMehdy, Monaen
dc.contributor.committeeMemberMorgan, Jenniferen
dc.contributor.committeeMemberGross, Jeffen
dc.creatorCheng, Ying-Hsienen
dc.date.accessioned2012-01-24T17:38:11Zen
dc.date.accessioned2017-05-11T22:23:50Z
dc.date.available2012-01-24T17:38:11Zen
dc.date.available2017-05-11T22:23:50Z
dc.date.issued2011-12en
dc.date.submittedDecember 2011en
dc.date.updated2012-01-24T17:38:23Zen
dc.descriptiontexten
dc.description.abstractThe BEACH family proteins are conserved in all eukaryotes and are important for membrane trafficking. Defects in specific BEACH proteins have been linked to severe human disorders. For example, loss of human LYST protein causes the Chediak-Higashi Syndrome (CHS), a lethal disorder that affects lysosomal function. I postulate that different classes of BEACH proteins contribute distinct cellular functions in specific organelles. Based on this functional specificity, I hypothesize that each class of BEACH proteins must localize to their respective organelle where they are known to function. Unfortunately, the localization of most mammalian BEACH proteins is not known and no localization signal has been determined for any BEACH protein. Previous work showed that the Dictyostelium LvsA protein localizes and functions on the contractile vacuole while LvsB localizes and functions on the lysosome. Thus, Dictyostelium is a good model system to understand how BEACH proteins localize to specific organelles. Using a knock-in approach and parasexual techniques, I generated a collection of LvsA truncation mutants tagged with GFP and expressed them in different cell lines. Hence I can test the ability of each mutant protein to localize on contractile vacuoles by fluorescence microscopy. I show here that LvsA requires two regions to localize on the contractile vacuole: the N-terminal 140-457 amino acids and the BEACH. In addition, the expression of the N-terminal 651 amino acids of LvsA causes a dominant negative effect suggesting a possible functional protein-protein interaction within this region. Furthermore, sequence alignment analysis shows that this N-terminal region is only conserved within each class of BEACH family proteins. This finding supports our hypothesis and suggests that diversity within the N-terminal region may be due to the specialized targeting sequences of each class of BEACH proteins. Taken together, these results suggest that the conserved BEACH domain may serve as a general localization sequence while the N-terminal segment is responsible for targeting these proteins to their distinct organelles. This study will facilitate the identification of localization signals in other BEACH proteins which is important to dissect the molecular mechanism of their respective functions.en
dc.description.departmentCellular and Molecular Biologyen
dc.format.mimetypeapplication/pdfen
dc.identifier.slug2152/ETD-UT-2011-12-4753en
dc.identifier.urihttp://hdl.handle.net/2152/ETD-UT-2011-12-4753en
dc.language.isoengen
dc.subjectLvsAen
dc.subjectBEACH proteinsen
dc.subjectContractile vacuoleen
dc.subjectLocalization signalen
dc.subjectCHS syndromnen
dc.titleLocalization of LvsA on the contractile vacuole in Dictyostelium discoideumen
dc.title.alternativeContractile vacuole localization signal of LvsA in Dictyostelium discoideumen
dc.type.genrethesisen

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