Nucleocytoplasmic shuttling of the ecdysteroid receptor (EcR) and of ultraspiracle (Usp) from Drosophila melanogaster in mammalian cells: energy requirement and interaction with exportin.
The small G protein Ran, which is important for nucleocytoplasmic shuttling of proteins is present, but does not interact with EcR, Usp, and EcR/Usp. As shown by oligomycin treatment, EcR, Usp, and EcR/Usp import is energy dependent. Export of EcR and EcR/Usp is mediated by exportin-1 (CRM-1) as shown by the inhibiting effect of leptomycin B (LMB). Usp remains in the nucleus for more than 24 h. Nuclear retainment of EcR and Usp is energy dependent as shown by treatment with oligomycin. No export signal could be identified for Usp. The data confirm that EcR and Usp can enter the nucleus independently and that intracellular localization is regulated individually for each receptor. It is also demonstrated that the export signal of EcR is inaccessible after heterodimerization with Usp.
Betanska
Katarzyna
K
Department of General Zoology and Endocrinology, University of Ulm, D-89069 Ulm, Germany.
Nieva
Claudia
C
Spindler-Barth
Margarethe
M
Spindler
Klaus-Dieter
KD
D021581:Active Transport, Cell Nucleus / Q000502:physiology*; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D004268:DNA-Binding Proteins / Q000378:metabolism*; D029721:Drosophila Proteins; D004331:Drosophila melanogaster; D004734:Energy Metabolism / Q000502:physiology*; D005231:Fatty Acids, Unsaturated; D006367:HeLa Cells; D006801:Humans; D028884:Karyopherins / Q000378:metabolism*; D009840:Oligomycins; D011485:Protein Binding; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D011987:Receptors, Steroid / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D000097606:Exportin 1 Protein
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D005231:Fatty Acids, Unsaturated; D028884:Karyopherins; D009840:Oligomycins; D018160:Receptors, Cytoplasmic and Nuclear; D011987:Receptors, Steroid; D014157:Transcription Factors; D000097606:Exportin 1 Protein; C066030:USP protein, Drosophila; C034808:ecdysteroid receptor; C038753:leptomycin B