scholarly journals Impaired Nuclear Translocation, Nuclear Matrix Targeting, and Intranuclear Mobility of Mutant Androgen Receptors Carrying Amino Acid Substitutions in the Deoxyribonucleic Acid-Binding Domain Derived from Androgen Insensitivity Syndrome Patients

2005 ◽  
Vol 90 (11) ◽  
pp. 6162-6169 ◽  
Author(s):  
Hisaya Kawate ◽  
Yin Wu ◽  
Keizo Ohnaka ◽  
Rong-Hua Tao ◽  
Kei-ichiro Nakamura ◽  
...  
Keyword(s):  
Fluorescence Recovery After Photobleaching ◽  
Deoxyribonucleic Acid ◽  
Fluorescent Protein ◽  
Nuclear Translocation ◽  
Androgen Insensitivity Syndrome ◽  
Cysteine Residue ◽  
Binding Domain ◽  
Wild Type ◽  
Androgen Insensitivity ◽  
Green Fluorescent

Abstract Context: Recent imaging studies revealed that androgen receptor (AR) is ligand-dependently translocated from the cytoplasm into the nucleus and forms intranuclear fine foci. In this study, we examined whether intracellular dynamics of mutant ARs detected in two androgen insensitivity syndrome (AIS) patients was impaired. Objective: ARs with mutations in the DNA-binding domain were functionally characterized and compared with the wild-type AR. Patients: In a complete AIS patient (subject 1), cysteine residue 579 in the first zinc finger motif of AR was substituted for phenylalanine (AR-C579F). Another mutation (AR-F582Y) was found in a partial AIS patient (subject 2). Results: AR-F582Y retained less than 10% of the transactivation activity of the wild-type AR, whereas no ligand-dependent transactivation was detected for AR-C579F. Image analyses of the receptors fused to green fluorescent protein showed that the wild-type AR was ligand-dependently translocated into the nucleus in which it formed fine subnuclear foci. Surprisingly, after the addition of dihydrotestosterone, the two mutant ARs initially formed large cytoplasmic dots, many of which were found to be close to mitochondria by electron microscopy. Subsequently, a part of the ligand-bound mutant ARs gradually entered the nucleus to form a smaller number of larger dots, compared with the wild-type AR. Fluorescence recovery after photobleaching analysis revealed that the intranuclear mobility of the mutant ARs decreased, compared with that of the wild-type AR. Conclusions: These results suggest that the abnormal translocation, localization, and mobility of the mutant ARs may be the cause of AIS in these subjects.

scholarly journals BiP prevents rod opsin aggregation

2012 ◽  
Vol 23 (18) ◽  
pp. 3522-3531 ◽  
Author(s):  
Dimitra Athanasiou ◽  
Maria Kosmaoglou ◽  
Naheed Kanuga ◽  
Sergey S. Novoselov ◽  
Adrienne W. Paton ◽  
...  
Keyword(s):  
Molecular Chaperones ◽  
Protein Misfolding ◽  
Fluorescence Recovery After Photobleaching ◽  
Fluorescent Protein ◽  
Wild Type ◽  
Rod Cells ◽  
Er Retention ◽  
Green Fluorescent ◽  
Subtilase Cytotoxin

Mutations in rod opsin—the light-sensitive protein of rod cells—cause retinitis pigmentosa. Many rod opsin mutations lead to protein misfolding, and therefore it is important to understand the role of molecular chaperones in rod opsin biogenesis. We show that BiP (HSPA5) prevents the aggregation of rod opsin. Cleavage of BiP with the subtilase cytotoxin SubAB results in endoplasmic reticulum (ER) retention and ubiquitylation of wild-type (WT) rod opsin (WT–green fluorescent protein [GFP]) at the ER. Fluorescence recovery after photobleaching reveals that WT-GFP is usually mobile in the ER. By contrast, depletion of BiP activity by treatment with SubAB or coexpression of a BiP ATPase mutant, BiP(T37G), decreases WT-GFP mobility to below that of the misfolding P23H mutant of rod opsin (P23H-GFP), which is retained in the ER and can form cytoplasmic ubiquitylated inclusions. SubAB treatment of P23H-GFP–expressing cells decreases the mobility of the mutant protein further and leads to ubiquitylation throughout the ER. Of interest, BiP overexpression increases the mobility of P23H-GFP, suggesting that it can reduce mutant rod opsin aggregation. Therefore inhibition of BiP function results in aggregation of rod opsin in the ER, which suggests that BiP is important for maintaining the solubility of rod opsin in the ER.

scholarly journals Ligand induced dissociation of the AR homodimer precedes AR monomer translocation to the nucleus

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ryota Shizu ◽  
Kosuke Yokobori ◽  
Lalith Perera ◽  
Lee Pedersen ◽  
Masahiko Negishi
Keyword(s):  
Sexual Development ◽  
Hormone Receptors ◽  
Nuclear Translocation ◽  
Steroid Hormone ◽  
Binding Pocket ◽  
Androgen Insensitivity Syndrome ◽  
Steroid Hormone Receptors ◽  
Wild Type ◽  
Dimer Interface ◽  
Androgen Insensitivity

Abstract The androgen receptor (AR) regulates male sexual development. We have now investigated AR homodimerization, hormone-dependent monomerization and nuclear translocation in PC-3 and COS-1 cells, by utilizing mutations associated with the androgen insensitivity syndrome: Pro767Ala, Phe765Leu, Met743Val and Trp742Arg. AR wild type (WT) was expressed as a homodimer in the cytoplasm, while none of these mutants formed homodimers. Unlike AR WT which responded to 1 nM dihydrotestosterone (DHT) to dissociate and translocate into the nucleus, AR Pro767Ala and Phe765Leu mutants remain as the monomer in the cytoplasm. In the crystal structure of the AR LBD homodimer, Pro767 and Phe765 reside closely on a loop that constitutes the dimer interface; their sidechains interact with the Pro767 of the other monomer and with the DHT molecule in the ligand-binding pocket. These observations place Phe765 at a position to facilitate DHT binding to Pro767 and lead to dissociation of the AR homodimer in the cytoplasm. This Pro-Phe Met relay may constitute a structural switch that mediates androgen signaling and is conserved in other steroid hormone receptors.

scholarly journals Mechanism of Aurora-B Degradation and Its Dependency on Intact KEN and A-Boxes: Identification of an Aneuploidy-Promoting Property

2005 ◽  
Vol 25 (12) ◽  
pp. 4977-4992 ◽  
Author(s):  
Hao G. Nguyen ◽  
Dharmaraj Chinnappan ◽  
Takeshi Urano ◽  
Katya Ravid
Keyword(s):  
Chromosome Segregation ◽  
Fluorescent Protein ◽  
Point Mutations ◽  
Degradation Pathway ◽  
Aurora B ◽  
Stable Form ◽  
Wild Type ◽  
Green Fluorescent ◽  
Critical Regions

ABSTRACT The kinase Aurora-B, a regulator of chromosome segregation and cytokinesis, is highly expressed in a variety of tumors. During the cell cycle, the level of this protein is tightly controlled, and its deregulated abundance is suspected to contribute to aneuploidy. Here, we provide evidence that Aurora-B is a short-lived protein degraded by the proteasome via the anaphase-promoting cyclosome complex (APC/c) pathway. Aurora-B interacts with the APC/c through the Cdc27 subunit, Aurora-B is ubiquitinated, and its level is increased upon treatment with inhibitors of the proteasome. Aurora-B binds in vivo to the degradation-targeting proteins Cdh1 and Cdc20, the overexpression of which accelerates Aurora-B degradation. Using deletions or point mutations of the five putative degradation signals in Aurora-B, we show that degradation of this protein does not depend on its D-boxes (RXXL), but it does require intact KEN boxes and A-boxes (QRVL) located within the first 65 amino acids. Cells transfected with wild-type or A-box-mutated or KEN box-mutated Aurora-B fused to green fluorescent protein display the protein localized to the chromosomes and then to the midzone during mitosis, but the mutated forms are detected at greater intensities. Hence, we identified the degradation pathway for Aurora-B as well as critical regions for its clearance. Intriguingly, overexpression of a stable form of Aurora-B alone induces aneuploidy and anchorage-independent growth.

scholarly journals Trafficking of Androgen Receptor Mutants Fused to Green Fluorescent Protein: A New Investigation of Partial Androgen Insensitivity Syndrome1

1998 ◽  
Vol 83 (10) ◽  
pp. 3597-3603 ◽  
Author(s):  
Virginie Georget ◽  
Béatrice Térouanne ◽  
Serge Lumbroso ◽  
Jean-Claude Nicolas ◽  
Charles Sultan
Keyword(s):  
Androgen Receptor ◽  
Green Fluorescent Protein ◽  
Fluorescent Protein ◽  
Protein A ◽  
Androgen Insensitivity ◽  
Green Fluorescent

scholarly journals Targeting of Protein Kinase C-ϵ during Fcγ Receptor-dependent Phagocytosis Requires the ϵC1B Domain and Phospholipase C-γ1

2006 ◽  
Vol 17 (2) ◽  
pp. 799-813 ◽  
Author(s):  
Keylon L. Cheeseman ◽  
Takehiko Ueyama ◽  
Tanya M. Michaud ◽  
Kaori Kashiwagi ◽  
Demin Wang ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phospholipase C ◽  
Phospholipase D ◽  
Fluorescent Protein ◽  
Wild Type ◽  
Fcγ Receptor ◽  
Kinase C ◽  
Green Fluorescent

Protein kinase C-ϵ (PKC-ϵ) translocates to phagosomes and promotes uptake of IgG-opsonized targets. To identify the regions responsible for this concentration, green fluorescent protein (GFP)-protein kinase C-ϵ mutants were tracked during phagocytosis and in response to exogenous lipids. Deletion of the diacylglycerol (DAG)-binding ϵC1 and ϵC1B domains, or the ϵC1B point mutant ϵC259G, decreased accumulation at phagosomes and membrane translocation in response to exogenous DAG. Quantitation of GFP revealed that ϵC259G, ϵC1, and ϵC1B accumulation at phagosomes was significantly less than that of intact PKC-ϵ. Also, the DAG antagonist 1-hexadecyl-2-acetyl glycerol (EI-150) blocked PKC-ϵ translocation. Thus, DAG binding to ϵC1B is necessary for PKC-ϵ translocation. The role of phospholipase D (PLD), phosphatidylinositol-specific phospholipase C (PI-PLC)-γ1, and PI-PLC-γ2 in PKC-ϵ accumulation was assessed. Although GFP-PLD2 localized to phagosomes and enhanced phagocytosis, PLD inhibition did not alter target ingestion or PKC-ϵ localization. In contrast, the PI-PLC inhibitor U73122 decreased both phagocytosis and PKC-ϵ accumulation. Although expression of PI-PLC-γ2 is higher than that of PI-PLC-γ1, PI-PLC-γ1 but not PI-PLC-γ2 consistently concentrated at phagosomes. Macrophages from PI-PLC-γ2-/-mice were similar to wild-type macrophages in their rate and extent of phagocytosis, their accumulation of PKC-ϵ at the phagosome, and their sensitivity to U73122. This implicates PI-PLC-γ1 as the enzyme that supports PKC-ϵ localization and phagocytosis. That PI-PLC-γ1 was transiently tyrosine phosphorylated in nascent phagosomes is consistent with this conclusion. Together, these results support a model in which PI-PLC-γ1 provides DAG that binds to ϵC1B, facilitating PKC-ϵ localization to phagosomes for efficient IgG-mediated phagocytosis.

scholarly journals Live-Cell Fluorescence Imaging Reveals the Dynamics of Protein Kinase CK2 Individual Subunits

2003 ◽  
Vol 23 (3) ◽  
pp. 975-987 ◽  
Author(s):  
Odile Filhol ◽  
Arsenio Nueda ◽  
Véronique Martel ◽  
Delphine Gerber-Scokaert ◽  
Maria José Benitez ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Nuclear Localization ◽  
Protein Kinase Ck2 ◽  
Fluorescent Protein ◽  
Nuclear Translocation ◽  
Nuclear Accumulation ◽  
Nucleocytoplasmic Trafficking ◽  
Green Fluorescent ◽  
Nucleocytoplasmic Distribution ◽  
Kinase Ck2

ABSTRACT Protein kinase CK2 is a multifunctional enzyme which has long been described as a stable heterotetrameric complex resulting from the association of two catalytic (α or α′) and two regulatory (β) subunits. To track the spatiotemporal dynamics of CK2 in living cells, we fused its catalytic α and regulatory β subunits with green fluorescent protein (GFP). Both CK2 subunits contain nuclear localization domains that target them independently to the nucleus. Imaging of stable cell lines expressing low levels of GFP-CK2α or GFP-CK2β revealed the existence of CK2 subunit subpopulations exhibiting differential dynamics. Once in the nucleus, they diffuse randomly at different rates. Unlike CK2β, CK2α can shuttle, showing the dynamic nature of the nucleocytoplasmic trafficking of the kinase. When microinjected in the cytoplasm, the isolated CK2 subunits are rapidly translocated into the nucleus, whereas the holoenzyme complex remains in this cell compartment, suggesting an intramolecular masking of the nuclear localization sequences that suppresses nuclear accumulation. However, binding of FGF-2 to the holoenzyme triggers its nuclear translocation. Since the substrate specificity of CK2α is dramatically changed by its association with CK2β, the control of the nucleocytoplasmic distribution of each subunit may represent a unique potential regulatory mechanism for CK2 activity.

Single amino acid substitution (840Arg → His) in the hormone-binding domain of the androgen receptor leads to incomplete androgen insensitivity syndrome associated with a thermolabile androgen receptor

1994 ◽  
Vol 130 (6) ◽  
pp. 569-574 ◽  
Author(s):  
Kyosuke Imasaki ◽  
Tomonobu Hasegawa ◽  
Taijiro Okabe ◽  
Yoshiyuki Sakai ◽  
Masafumi Haji ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Amino Acid ◽  
Amino Acid Substitution ◽  
Androgen Insensitivity Syndrome ◽  
Binding Domain ◽  
Single Amino Acid Substitution ◽  
Single Amino Acid ◽  
Hormone Binding ◽  
Androgen Insensitivity ◽  
Hormone Binding Domain

Imasaki K, Hasegawa T. Okabe T. Sakai Y. Haji M. Takayanagi R, Nawata H. Single amino acid substitution (840Arg → His) in the hormone-binding domain of the androgen receptor leads to incomplete androgen insensitivity syndrome associated with a thermolabile androgen receptor. Eur I Endocrinol 1994;130:569–74. ISSN 0804–4643 We have characterized the androgen receptor in a Japanese girl and her maternal cousin in a family with incomplete androgen insensitivity syndrome, and have investigated the molecular basis. Wholecell androgen binding assay in cultured genital skin fibroblasts from both patients showed a normal maximum binding capacity and a normal apparent dissociation constant. However, androgen binding in fibroblasts from both patients decreased to 30% when the assay temperature was raised from 30°C to 41°C, indicating the presence of the thermolability of ligand binding to the androgen receptor. Sequence analysis of the coding exons of the androgen receptor gene from the patients revealed a single nucleotide substitution at position 2881 in exon G, resulting in the conversion of arginine (CGT) to histidine (CAT) at amino acid position 840 in the hormone-binding domain of the androgen receptor. The family study showed that the mothers and the maternal grandmother of the patients are heterozygous carriers for this mutation, whereas the father does not carry it, supporting the view that androgen insensitivity syndrome is an X chromosome-linked disorder. The single amino acid substitution may explain the qualitative abnormality of the androgen receptor displaying thermolability, which is thought to be the pathogenesis of incomplete androgen insensitivity syndrome in the patients. Kyosuke Imasaki, Third Department of Internal Medicine, Faculty of Medicine, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812, Japan

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