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Updated: Jun 6, 2026

Heterokaryon Technique for Analysis of Cell Type-specific Localization
Published on: March 11, 2011
The importance of exportin and Ran for nucleocytoplasmic shuttling of the ecdysteroid receptor
Katarzyna Betanska1, Celine Hönl, Margarethe Spindler-Barth
1Institute of General Zoology and Endocrinology, University of Ulm, Ulm, Germany.
Abstract:
Nuclear localization of the ecdysteroid receptor (EcR) is increased in HeLa cells if exportin-1 (CRM1), a predominant carrier for export of proteins and RNA from the nucleus into the cytoplasm, is knocked down by siRNA against exportin. However, knockdown of the small G protein Ran, which is essential for nuclear transport, leads to an arrest of EcR in the cytoplasm, but does not prevent efficient nuclear import of the most important heterodimerization partner of EcR, ultraspiracle (Usp). Like in vertebrate cells, EcR is also distributed heterogeneously in Drosophila melanogaster S2 cells but shifted exclusively to the nucleus, if Usp is present.
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