The ubiquitin system is a major cytosolic and nuclear pathway of proteolysis in all eukaryotic cells. In this pathway, ubiquitin, a 76 amino acid peptide, is covalently ligated to protein substrates by a series of enzymes; E1, E2 and E3. The ubiquitin-attached proteins are commonly targeted for destruction by the 26S proteasome but the ubiquitination may also direct other cellular functions such as endocytosis, leading to proteolysis in the lysosome. Interestingly, a large family of genes encoding deubiquitinating enzymes (UBP; ubiquitin specific processing protease and UCH; ubiquitin C-terminal hydrolase) has recently been identified from different organisms. These enzymes are found to remove ubiquitin from covalent attachments to itself or other proteins in order to regenerate free ubiquitin or to counteract the effects of ubiquitinating enzymes by removing the polyubiquitin chain from the conjugated protein substrate. Dr. Wing's laboratory has recently identified USP2a and USP2b, two germ cell specific UBP isoforms that share a common core region but divergent N-termini. These termini target the USP2b and USP2a to different subcellular locations and also influence substrate specificity. / To identify substrates or interacting proteins that may serve to localize these enzymes, a bacterial two-hybrid assay was performed using a mouse testis cDNA library and the N-termini of the enzymes as baits. Kpna6, an isoform of Karyopherin alpha (also known as importin alpha) and SKD3, the suppressor of K + transport defect protein were found to be possible interacting proteins of USP2a and USP2b respectively.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.81352 |
| Date | January 2004 |
| Creators | Lee, Kyung-Joo, 1977- |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Division of Experimental Medicine.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 002166610, proquestno: AAIMR06415, Theses scanned by UMI/ProQuest. |
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