Disruption of microtubules leads to glucocorticoid receptor degradation in HeLa cell line.
The role of microtubules (MTs) in steroid hormone-dependent human glucocorticoid receptor (hGR) activation/translocation is controversial. It was demonstrated recently that colchicine (COL) down-regulates hGR-driven genes in primary human hepatocytes by a mechanism involving inhibition of hGR translocation to the nucleus. To investigate whether inhibition of hGR translocation is the sole reason for its inactivation, we used human cervical carcinoma cells (HeLa) as a model. Herein we present evidence that perturbation of microtubules in HeLa cells leads to rapid time- and dose-dependent degradation of hGR protein. Degradation is proteasome mediated as revealed by its reversibility by proteasome inhibitor MG132. Moreover, degradation was observed for neither wt-hGR nor hGR mutants S226A and K419A in transiently transfected COS-1 cells. On the other hand, c-jun N-terminal kinase (JNK) seems not to be involved in the process because JNK inhibitor 1,9-Pyrazoloanthrone (SP600125) does not reverse hGR degradation. Similarly, another hGR functional antagonist, nuclear factor kappa beta (NFkappaB), did not play any role in the degradation process.
Dvorák
Zdenek
Z
Institute of Medical Chemistry and Biochemistry, Medical Faculty, Palacký University Olomouc, Hnevotínská 3, 77515 OLOMOUC, Czech Republic. moulin@email.cz
Modrianský
Martin
M
Ulrichová
Jitka
J
Maurel
Patrick
P
Vilarem
Marie-Jose
MJ
Pascussi
Jean-Marc
JM
D000818:Animals; D000873:Anthracenes / Q000494:pharmacology; D019556:COS Cells; D002522:Chlorocebus aethiops; D003078:Colchicine / Q000494:pharmacology; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D042581:Intranuclear Space / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D007976:Leupeptins / Q000494:pharmacology; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D009154:Mutation / Q000502:physiology; D016328:NF-kappa B / Q000378:metabolism; D015739:Nocodazole / Q000494:pharmacology; D046988:Proteasome Endopeptidase Complex / Q000187:drug effects / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects; D011965:Receptors, Glucocorticoid / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D025801:Ubiquitin / Q000378:metabolism; D014750:Vincristine / Q000494:pharmacology
D000873:Anthracenes; D015853:Cysteine Proteinase Inhibitors; D004791:Enzyme Inhibitors; D007976:Leupeptins; D016328:NF-kappa B; D011965:Receptors, Glucocorticoid; D025801:Ubiquitin; C432165:pyrazolanthrone; D014750:Vincristine; D003907:Dexamethasone; D048031:JNK Mitogen-Activated Protein Kinases; D046988:Proteasome Endopeptidase Complex; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde; D015739:Nocodazole; D003078:Colchicine