Karyopherin? proteins mediate nucleocytoplasmic transport through recognition of distinct nuclear localization or export signals (NLSs or NESs). Although there are 19 known Kaps in humans, only three classes of signals for Kap?/Kap?1, Kap?2 (or Transportin) and CRM1, respectively, are known at this time. Most other Kaps recognize diverse sequences that occlude the identity of their signals. This proposal describes structural and biochemical analyses of import systems Kap?2 and Imp5/Kap121 as well as the export-Kap CRM1. Kap?2 mediates nuclear import of RNA binding proteins through their PY-NLSs. Our discovery and understanding of the PY-NLS contributed to the discovery of a defective PY-NLS that causes a subset of amyotrophic lateral sclerosis (ALS). Here, we propose to understand the role of Kap?2 in protein mislocalization and aggregation in ALS. In another aim, we will apply the combined structural, biochemical and bioinformatics approach that we used to discover the PY-NLS to the Imp5/Kap121p pathway with the goal of discovering a set of characteristics to unify the diverse sequences recognized by the Kaps, hence revealing a new class of NLS. Finally, we will study CRM1, which mediates nuclear export of hundreds of proteins;most of them identified using the small molecule inhibitor Leptomycin B. This proposal aims to determine the mechanism of how CRM1 mediates conjugation of leptomycin B to inhibit nuclear export.

Public Health Relevance

Many proteins are mislocalized in diseases such as amyotrophic lateral sclerosis and cancer. It is important to understand how proteins are targeted correctly since correcting protein mislocalization may be a valid disease therapy.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM069909-10
Application #
8440064
Study Section
Nuclear and Cytoplasmic Structure/Function and Dynamics Study Section (NCSD)
Program Officer
Ainsztein, Alexandra M
Project Start
2004-02-01
Project End
2017-01-31
Budget Start
2013-02-01
Budget End
2014-01-31
Support Year
10
Fiscal Year
2013
Total Cost
$333,488
Indirect Cost
$123,747
Name
University of Texas Sw Medical Center Dallas
Department
Pharmacology
Type
Schools of Medicine
DUNS #
800771545
City
Dallas
State
TX
Country
United States
Zip Code
75390
Bernis, Cyril; Swift-Taylor, Beth; Nord, Matthew et al. (2014) Transportin acts to regulate mitotic assembly events by target binding rather than Ran sequestration. Mol Biol Cell 25:992-1009
Fung, Ho Yee Joyce; Chook, Yuh Min (2014) Atomic basis of CRM1-cargo recognition, release and inhibition. Semin Cancer Biol 27:52-61
Sun, Qingxiang; Carrasco, Yazmin P; Hu, Youcai et al. (2013) Nuclear export inhibition through covalent conjugation and hydrolysis of Leptomycin B by CRM1. Proc Natl Acad Sci U S A 110:1303-8
Etchin, J; Sun, Q; Kentsis, A et al. (2013) Antileukemic activity of nuclear export inhibitors that spare normal hematopoietic cells. Leukemia 27:66-74
Soniat, Michael; Sampathkumar, Parthasarathy; Collett, Garen et al. (2013) Crystal structure of human Karyopherin *2 bound to the PY-NLS of Saccharomyces cerevisiae Nab2. J Struct Funct Genomics 14:31-5
Zhang, Zi Chao; Satterly, Neal; Fontoura, Beatriz M A et al. (2011) Evolutionary development of redundant nuclear localization signals in the mRNA export factor NXF1. Mol Biol Cell 22:4657-68
Chook, Yuh Min; Suel, Katherine E (2011) Nuclear import by karyopherin-*s: recognition and inhibition. Biochim Biophys Acta 1813:1593-606
Xu, Darui; Farmer, Alicia; Chook, Yuh Min (2010) Recognition of nuclear targeting signals by Karyopherin-ýý proteins. Curr Opin Struct Biol 20:782-90
Suel, Katherine E; Chook, Yuh Min (2009) Kap104p imports the PY-NLS-containing transcription factor Tfg2p into the nucleus. J Biol Chem 284:15416-24
Dong, Xiuhua; Biswas, Anindita; Suel, Katherine E et al. (2009) Structural basis for leucine-rich nuclear export signal recognition by CRM1. Nature 458:1136-41

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