This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Many cargoes destined for nuclear import carry nuclear localization signals that are recognized by karyopherins (Kaps). We present methods to quantitate import rates and measure Kap and cargo concentrations in single yeast cells in vivo, providing new insights into import kinetics. By systematically manipulating the amounts, types, and affinities of Kaps and cargos, we show that import rates in vivo are simply governed by the concentrations of Kaps and their cargo and the affinity between them. These rates fit to a straightforward pump-leak model for the import process. Unexpectedly, we deduced that the main limiting factor for import is the poor ability of Kaps and cargos to find each other in the cytoplasm in a background of overwhelming nonspecific competition, rather than other more obvious candidates such as the nuclear pore complex and Ran. It is likely that most of every import round is taken up by Kaps and nuclear localization signals sampling other cytoplasmic proteins as they locate each other in the cytoplasm. a manuscript describing the early stages of this work has been published: Simple kinetic relationships and nonspecific competition govern nuclear import rates in vivo. Timney BL, Tetenbaum-Novatt J, Agate DS, Williams R, Zhang W, Chait BT, Rout MP.J Cell Biol. 2006 175(4):579-93. Currently this work is being expanded to include measurements of the dissociation constants between a variety of transport factors and FG-nucleoporins.
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| Boice, Michael; Salloum, Darin; Mourcin, Frederic et al. (2016) Loss of the HVEM Tumor Suppressor in Lymphoma and Restoration by Modified CAR-T Cells. Cell 167:405-418.e13 |
| Chait, Brian T; Cadene, Martine; Olinares, Paul Dominic et al. (2016) Revealing Higher Order Protein Structure Using Mass Spectrometry. J Am Soc Mass Spectrom 27:952-65 |
| Krutchinsky, Andrew N; Padovan, Júlio C; Cohen, Herbert et al. (2015) Maximizing ion transmission from atmospheric pressure into the vacuum of mass spectrometers with a novel electrospray interface. J Am Soc Mass Spectrom 26:649-58 |
| Mast, Fred D; Rachubinski, Richard A; Aitchison, John D (2015) Signaling dynamics and peroxisomes. Curr Opin Cell Biol 35:131-6 |
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| Zhong, Yu; Morris, Deanna H; Jin, Lin et al. (2014) Nrbf2 protein suppresses autophagy by modulating Atg14L protein-containing Beclin 1-Vps34 complex architecture and reducing intracellular phosphatidylinositol-3 phosphate levels. J Biol Chem 289:26021-37 |
| Indiani, Chiara; O'Donnell, Mike (2013) A proposal: Source of single strand DNA that elicits the SOS response. Front Biosci (Landmark Ed) 18:312-23 |
| Di Virgilio, Michela; Callen, Elsa; Yamane, Arito et al. (2013) Rif1 prevents resection of DNA breaks and promotes immunoglobulin class switching. Science 339:711-5 |
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