A Serine/Threonine-rich Motif Is One of Three Nuclear Localization Signals That Determine Unidirectional Transport of the Mineralocorticoid Receptor to the Nucleus

Autor: Amanda Carrigan, Laura Visentin, Ella Atlas, Gregory C. Addicks, Yanouchka Rouleau, Allison Edgecombe, Claudia Lamprecht, Yvonne A. Lefebvre, Robert J. G. Haché, Rhian F. Walther
Rok vydání: 2005
Předmět:
Threonine
Cytoplasm
Time Factors
Amino Acid Motifs
Blotting
Western
Green Fluorescent Proteins
Molecular Sequence Data
Nuclear Localization Signals
Active Transport
Cell Nucleus
Biology
Ligands
Transfection
Biochemistry
Receptors
Glucocorticoid
Serine
Animals
Humans
Nuclear Matrix
Amino Acid Sequence
Phosphorylation
Fluorescent Antibody Technique
Indirect
Nuclear export signal
Molecular Biology
Nuclear receptor co-repressor 1
Glutathione Transferase
Cell Nucleus
Biological Transport
Cell Biology
Protein Structure
Tertiary
Cell biology
Nuclear receptor coactivator 1
Receptors
Mineralocorticoid
Nuclear receptor
COS Cells
Nuclear receptor coactivator 3
Nuclear receptor coactivator 2
Steroids
Nuclear transport
Nuclear localization sequence
Fluorescence Recovery After Photobleaching
HeLa Cells
Plasmids
Zdroj: Journal of Biological Chemistry. 280:17549-17561
ISSN: 0021-9258
Popis: The mineralocorticoid receptor (MR) is a tightly regulated nuclear hormone receptor that selectively transmits corticosteroid signals. Steroid treatment transforms MR from a transcriptionally inert state, in which it is distributed equally between the nucleus and cytoplasm, to an active completely nuclear transcription factor. We report here that MR is an atypical nuclear hormone receptor that moves unidirectionally from the cytoplasm to the nucleus. We show that nuclear import of MR is controlled through three nuclear localization signals (NLSs) of distinct types. Nuclear localization of naive MR was mediated primarily through a novel serine/threonine-rich NLS (NL0) in the receptor N terminus. Specific amino acid substitutions that mimicked phosphorylation selectively enhanced or repressed NL0 activity, highlighting the potential for active regulation of this new type of NLS. The second NLS (NL2) within the ligand-binding domain also lacks a recognizable basic motif. Nuclear transfer through this signal was strictly dependent on steroid agonist, but was independent of the interaction of MR with coactivator proteins. The third MR NLS (NL1) is a bipartite basic motif localized to the C terminus of the MR DNA-binding domain with properties distinct from those of NL1 of the closely related glucocorticoid receptor. NL1 acted in concert with NL0 and NL2 to stimulate nuclear uptake of the agonist-treated receptor, but also directed the complete nuclear localization of MR in response to treatment with steroid antagonist. These results present MR as a nuclear hormone receptor whose unidirectional transfer to the nucleus may be regulated through multiple pathways.
Databáze: OpenAIRE
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