PMCCPMCCPMCC

Search tips
Search criteria 

Advanced

 
Logo of jcellbiolHomeThe Rockefeller University PressEditorsContactInstructions for AuthorsThis issue
 
J Cell Biol. Dec 2, 1996; 135(6): 1457–1470.
PMCID: PMC2133973
A novel ubiquitin-like modification modulates the partitioning of the Ran-GTPase-activating protein RanGAP1 between the cytosol and the nuclear pore complex
Abstract
Ran is a nuclear Ras-like GTPase that is required for the bidirectional transport of proteins and ribnucleoproteins across the nuclear pore complex (NPC). A key regulator of the Ran GTP/GDP cycle is the 70-kD Ran-GTPase-activating protein RanGAP1. Here, we report the identification and localization of a novel form of RanGAP1. Using peptide sequence analysis and specific mAbs, RanGAP1 was found to be modified by conjugation to a ubiquitin-like protein. Immunoblot analysis and immunolocalization by light and EM demonstrated that the 70-kD unmodified from of RanGAP1 is exclusively cytoplasmic, whereas the 90-kD modified form of RanGAP1 is associated with the cytoplasmic fibers of the NPC. The modified form of RanGAP1 also appeared to associated with the mitotic spindle apparatus during mitosis. These findings have specific implications for Ran function and broad implications for protein regulation by ubiquitin-like modifications. Moreover, the variety and function of ubiquitin-like protein modifications in the cell may be more diverse than previously realized.
Full Text
The Full Text of this article is available as a PDF (3.4M).
Articles from The Journal of Cell Biology are provided here courtesy of
The Rockefeller University Press