JCB logo
Accuri Cytometers
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents
This Article
Right arrow Full Text
Right arrow Full Text (PDF, 452K)
Right arrow PPT slides of all figures
Right arrow Alert me when this article is cited
Right arrow Citation Map
Services
Right arrow Email this article
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new content in the JCB
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Paraskeva, E.
Right arrow Articles by Görlich, D.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Paraskeva, E.
Right arrow Articles by Görlich, D.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?

J. Cell Biol., Volume 145, Number 2, April 19, 1999 255-264

CRM1-mediated Recycling of Snurportin 1 to the Cytoplasm

Efrosyni Paraskeva,* Elisa Izaurralde,Dagger F. Ralf Bischoff,§ Jochen Huber,parallel Ulrike Kutay,* Enno Hartmann, Reinhard Lührmann,parallel and Dirk Görlich*

* Zentrum für Molekulare Biologie der Universität Heidelberg, D-69120 Heidelberg, Germany; Dagger  University of Geneva, Department of Molecular Biology, CH-1211 Geneva 4, Switzerland; § Abteilung Molekulare Biologie der Mitose, Deutsches Krebsforschungszentrum, D-69120 Heidelberg, Germany; parallel  Institut für Molekularbiologie und Tumorforschung, D-35037 Marburg, Germany; and  Zentrum Biochemie und Molekulare Zellbiologie, Abteilung Biochemie II, D-37073 Göttingen, Germany

Importin beta  is a major mediator of import into the cell nucleus. Importin beta  binds cargo molecules either directly or via two types of adapter molecules, importin alpha , for import of proteins with a classical nuclear localization signal (NLS), or snurportin 1, for import of m3G-capped U snRNPs. Both adapters have an NH2-terminal importin beta -binding domain for binding to, and import by, importin beta , and both need to be returned to the cytoplasm after having delivered their cargoes to the nucleus. We have shown previously that CAS mediates export of importin alpha . Here we show that snurportin 1 is exported by CRM1, the receptor for leucine-rich nuclear export signals (NESs). However, the interaction of CRM1 with snurportin 1 differs from that with previously characterized NESs. First, CRM1 binds snurportin 1 50-fold stronger than the Rev protein and 5,000-fold stronger than the minimum Rev activation domain. Second, snurportin 1 interacts with CRM1 not through a short peptide but rather via a large domain that allows regulation of affinity. Strikingly, snurportin 1 has a low affinity for CRM1 when bound to its m3G-capped import substrate, and a high affinity when substrate-free. This mechanism appears crucial for productive import cycles as it can ensure that CRM1 only exports snurportin 1 that has already released its import substrate in the nucleus.

Key words: nuclear transport;  nuclear pore complex;  importin;  exportin;  snurportin 1


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati    What's this?


This article has been cited by other articles:



  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents