Transport of nucleic acids and proteins between the nucleus and cytoplasm occurs exclusively through nuclear pore complexes (NPCs), large transport channels embedded in the nuclear envelope. Molecules larger than ~40kDa are largely excluded from moving through the NPC unless bound by a specialized transport receptor. Cargo macromolecules bind a transport receptor, which in turn interacts with a subset of NPC proteins containing phenylalanine-glycine (FG) repeat domains. Trafficking of a transport receptor-cargo complex through the NPC requires stochastic, low-affinity interactions between the transport receptor and FG repeat domains. More than a third of the ~30 NPC proteins harbor FG repeat domains, and each FG repeat domain potentially serves as a binding site for transport receptors at intermediate points in nucleocytoplasmic transport. Whether each of the ~15 transport receptors in yeast preferentially binds a subset of these FG domains is unresolved. In this study, we used genetic strategies in Saccharomyces cerevisiae to systematically delete (∆) combinations of FG domains. We assayed these FG∆ mutants for defects in trafficking of several different transport receptors, including a specific focus on messenger RNA (mRNA) export. We found that mRNA export and specific protein import receptors require different subsets of FG domains. This result indicates that there are multiple transport pathways through the NPC, each of which is defined by preferential binding of a transport receptor to a subset of FG domains. Additionally, we found that FG domains located on the nuclear side of the NPC contribute to recruiting the mRNA export receptor to the NPC. Further, FG domains positioned on the cytoplasmic side of the NPC might regulate terminal events in mRNA export. As a whole, these results suggest that each FG domain might play a regulatory role in mediating efficient movement of specific transport receptors through the NPC.
| Identifer | oai:union.ndltd.org:VANDERBILT/oai:VANDERBILTETD:etd-12052008-104202 |
| Date | 30 December 2008 |
| Creators | Terry, Laura Jennings |
| Contributors | Katherine L. Friedman, Todd R. Graham, Byeong J. Cha, James G. Goldenring, Susan R. Wente |
| Publisher | VANDERBILT |
| Source Sets | Vanderbilt University Theses |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.vanderbilt.edu/available/etd-12052008-104202/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Vanderbilt University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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