Important note: Information in this article was accurate in 1999. The state of the art may have changed since the publication date.
The nucleoporin nup153 plays a critical role in multiple types of nuclear export.
Mol Biol Cell. 1999 Mar;10(3):649-64. Unique Identifier : AIDSLINE MED/99169012 Ullman KS; Shah S; Powers MA; Forbes DJ; Department of Biology, University of California at San Diego, La; Jolla, California 92093-0347, USA. katharine.ullman@hci.utah.edu
Abstract:
The fundamental process of nucleocytoplasmic transport takes place through the nuclear pore. Peripheral pore structures are presumably poised to interact with transport receptors and their cargo as these receptor complexes first encounter the pore. One such peripheral structure likely to play an important role in nuclear export is the basket structure located on the nuclear side of the pore. At present, Nup153 is the only nucleoporin known to localize to the surface of this basket, suggesting that Nup153 is potentially one of the first pore components an RNA or protein encounters during export. In this study, anti-Nup153 antibodies were used to probe the role of Nup153 in nuclear export in Xenopus oocytes. We found that Nup153 antibodies block three major classes of RNA export, that of snRNA, mRNA, and 5S rRNA. Nup153 antibodies also block the NES protein export pathway, specifically the export of the HIV Rev protein, as well as Rev-dependent RNA export. Not all export was blocked; Nup153 antibodies did not impede the export of tRNA or the recycling of importin beta to the cytoplasm. The specific antibodies used here also did not affect nuclear import, whether mediated by importin alpha/beta or by transportin. Overall, the results indicate that Nup153 is crucial to multiple classes of RNA and protein export, being involved at a vital juncture point in their export pathways. This juncture point appears to be one that is bypassed by tRNA during its export. We asked whether a physical interaction between RNA and Nup153 could be observed, using homoribopolymers as sequence-independent probes for interaction. Nup153, unlike four other nucleoporins including Nup98, associated strongly with poly(G) and significantly with poly(U). Thus, Nup153 is unique among the nucleoporins tested in its ability to interact with RNA and must do so either directly or indirectly through an adaptor protein. These results suggest a unique mechanistic role for Nup153 in the export of multiple cargos.
Keywords: JOURNAL ARTICLE Animal Antibodies/METABOLISM/PHARMACOLOGY Biological Transport/DRUG EFFECTS Cell Nucleus/*METABOLISM Female Gene Products, rev/METABOLISM Nuclear Proteins/IMMUNOLOGY/*METABOLISM Oocytes/DRUG EFFECTS/METABOLISM Poly G/METABOLISM Poly U/METABOLISM RNA/METABOLISM RNA Precursors/METABOLISM RNA, Small Nuclear/METABOLISM Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Xenopus 990630
A9960993
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Important note: Information in this article was accurate in 1999. The state of the art may have changed since the publication date.
