Jutta Mayr, Huei-Rong Wang, Petra Nederlof, Wolfgang Baumeister
The Import Pathway of Human and Thermoplasma 20S Proteasomes into HeLa Cell Nuclei Is Different from That of Classical NLS-Bearing Proteins
Wild-type proteasomes of human erythrocytes and the archaeon Thermoplasma acidophilum compete with each other for transport into nuclei of digitonin-permeabilized HeLa cells in the presence of an energy-regenerating system and rabbit reticulocyte lysate. ‘NLS’-mutated Thermoplasma proteasomes were also able to compete with human proteasomes in the same assay, although with lower efficiency. Furthermore, in contrast to the other archaeal and bacterial cell lysates tested, the Thermoplasma cytosol efficiently supported nuclear import of human and Thermoplasma proteasomes. However, the same lysate could barely direct the nuclear transport of BSA-NLSSV40 peptide conjugates or the classical NLS-bearing protein, nucleoplasmin. Finally, additional importin ?/? significantly decreased the import efficiency of both human and Thermoplasma proteasomes. Taken together, these results suggest that nuclear import of proteasomes may use a novel pathway that is different from that of classical NLS-bearing proteins.
Biological Chemistry, Walter de Gruyter
Print ISSN: 1431-6730
Volume: 380, 10/1999
Pages: 1183 - 1192
Show full article (external site)
Show all available items of this journal
Search
