{"@context":"http://iiif.io/api/presentation/2/context.json","@id":"https://repo.library.stonybrook.edu/cantaloupe/iiif/2/manifest.json","@type":"sc:Manifest","label":"A Role for O-Fucosylation in the Folding of Thrombospondin Type I Repeats","metadata":[{"label":"dc.description.sponsorship","value":"This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree."},{"label":"dc.format","value":"Monograph"},{"label":"dc.format.medium","value":"Electronic Resource"},{"label":"dc.identifier.uri","value":"http://hdl.handle.net/11401/76932"},{"label":"dc.language.iso","value":"en_US"},{"label":"dc.publisher","value":"The Graduate School, Stony Brook University: Stony Brook, NY."},{"label":"dcterms.abstract","value":"Protein <italic>O</italic>-fucosyltransferase 2 (Pofut2) is a soluble, ER localized enzyme that adds a fucose residue to specific Serines and Threonines found in Thrombospondin type I repeats (TSRs). TSRs are small, cysteine-rich motifs usually found as tandem repeats. The current consensus sequence for <italic>O</italic>-fucosylation is CXX(S/T)CXXG. Database searches with the consensus sequence predict fifty TSR-containing protein targets for Pofut2. The <italic>O</italic>-fucose on TSRs is extended by the addition of a &beta; 1,3-glucose, catalyzed by &beta; 3-glucosyltransferase (&beta; 3GlcT). Pofut2 knockout mice are early embryonic lethal while &beta; 3GlcT mutations in humans cause a development disorder called Peters plus syndrome. To understand Pofut2 and &beta; 3GlcT phenotypes, it is important to deduce the molecular role of <italic>O</italic>-fucosylation.   Pofut2 can distinguish between properly folded and unfolded TSRs <italic>in vitro</italic>. Taken together with its localization to the ER, a protein-folding compartment, we have hypothesized that Pofut2 plays a role in quality control. Eliminating the donor substrate, GDP-fucose, or Pofut2, results in loss of secretion of two targets - ADAMTS13 and ADAMTSL1. In this thesis, I extend these observations to other Pofut2 targets and demonstrate that Pofut2 has a dual role as a chaperone and fucosyltransferase. I show that both the number of tandem TSRs and the primary amino acid sequence influence fucose-dependent secretion. I demonstrate that <italic>O</italic>-fucosylation is both co-translational and post-translational. I show that in the absence of GDP-fucose, Pofut2 binds more tightly to its substrates, providing a potential explanation for why elimination of GDP-fucose results in decreased secretion of target proteins. I also identify several ER-resident proteins that are in complex with Pofut2, potentially assisting in the folding of TSRs and retaining Pofut2 in the ER. Mature TSRs from target proteins show high stoichiometries of O-fucosylation, whereas most cell-associated proteins are aggregated, partially folded and poorly fucosylated. A small portion of cell-associated protein is mostly folded and is nearly fully fucosylated, suggesting that <italic>O</italic>-fucosylation is a marker of properly folded TSRs in the cell. Finally, I establish a direct role for Pofut2 in the folding of TSRs in vitro and determine that both GDP-fucose and enzymatic activity are required for this process."},{"label":"dcterms.available","value":"2017-09-20T16:51:28Z"},{"label":"dcterms.contributor","value":"Majerus, Elaine."},{"label":"dcterms.creator","value":"Vasudevan, Deepika"},{"label":"dcterms.dateAccepted","value":"2017-09-20T16:51:28Z"},{"label":"dcterms.dateSubmitted","value":"2017-09-20T16:51:28Z"},{"label":"dcterms.description","value":"Department of Biochemistry and Cell Biology."},{"label":"dcterms.extent","value":"143 pg."},{"label":"dcterms.format","value":"Application/PDF"},{"label":"dcterms.identifier","value":"http://hdl.handle.net/11401/76932"},{"label":"dcterms.issued","value":"2015-08-01"},{"label":"dcterms.language","value":"en_US"},{"label":"dcterms.provenance","value":"Made available in DSpace on 2017-09-20T16:51:28Z (GMT). No. of bitstreams: 1\nVasudevan_grad.sunysb_0771E_11634.pdf: 12079334 bytes, checksum: 301523a3860f08bb04196f1f5598bb70 (MD5)\n  Previous issue date: 2013"},{"label":"dcterms.publisher","value":"The Graduate School, Stony Brook University: Stony Brook, NY."},{"label":"dcterms.subject","value":"Chaperone, Folding, O-Fucosylation, Pofut2, TSR"},{"label":"dcterms.title","value":"A Role for O-Fucosylation in the Folding of Thrombospondin Type I Repeats"},{"label":"dcterms.type","value":"Dissertation"},{"label":"dc.type","value":"Dissertation"}],"description":"This manifest was generated dynamically","viewingDirection":"left-to-right","sequences":[{"@type":"sc:Sequence","canvases":[{"@id":"https://repo.library.stonybrook.edu/cantaloupe/iiif/2/canvas/page-1.json","@type":"sc:Canvas","label":"Page 1","height":1650,"width":1275,"images":[{"@type":"oa:Annotation","motivation":"sc:painting","resource":{"@id":"https://repo.library.stonybrook.edu/cantaloupe/iiif/2/64%2F98%2F56%2F64985620429519829230216833031399277903/full/full/0/default.jpg","@type":"dctypes:Image","format":"image/jpeg","height":1650,"width":1275,"service":{"@context":"http://iiif.io/api/image/2/context.json","@id":"https://repo.library.stonybrook.edu/cantaloupe/iiif/2/64%2F98%2F56%2F64985620429519829230216833031399277903","profile":"http://iiif.io/api/image/2/level2.json"}},"on":"https://repo.library.stonybrook.edu/cantaloupe/iiif/2/canvas/page-1.json"}]}]}]}