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Proteins that interact with ubiquitin-conjugating enzyme 2, UBC-2, in the nematode Caenorhabditis elegans

University of British Columbia

A major route for protein degradation occurs via the ubiquitin-proteasome pathway. Proteins are targeted for destruction by the proteasome through covalent ubiquitin attachment. This tagging system involves the concerted action of an ubiquitin-activating enzyme (El), an ubiquitin-conjugating enzyme (E2), and an ubiquitin ligase (E3), with the latter two being involved in achieving target specificity. UBC-2, an essential E2 in the nematode C. elegans, is a functional homolog of Saccharomyces cerevisiae UBC4, a member of a branch of ubiquitin-conjugating enzymes required for the degradation of short-lived and abnormal proteins. In order to identify proteins that interact with UBC-2, a yeast two-hybrid analysis was employed. Putative TJBC-2 interacting proteins identified include: a ubiquitin-like budding yeast DSK2 ortholog referred to as DSK-2, two RING finger proteins, a protein containing a FYVE domain, a calcium ATPase called MCA-1, and ubiquitin. Since DSK-2 represented 60% of the putative interactors isolated from the screen, this project focused on the interaction of UBC-2 and DSK-2, and demonstrated a novel interaction between an E2 and an ubiquitin-domain protein (UDP) in vitro. The ability of DSK-2 to bind polyubiquitin and itself was also demonstrated. RNA interference (RNAi) was employed in an attempt to determine the biological function of UBC-2 interacting proteins in vivo. RNAi with mca-1 produced a subtle body shortening phenotype, although genes encoding UBC-2 interacting proteins appear to be non-essential.

Thesis/Dissertation

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2009-09-18

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http://hdl.handle.net/2429/12917

Biochemistry and Molecular Biology

University of British Columbia

UBCV

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