Aurora A kinase interacts with and phosphorylates VHL protein

Biologia ◽  
2012 ◽  
Vol 67 (5) ◽  
Author(s):  
Imen Ferchichi ◽  
Yannick Arlot ◽  
Jean-Yves Cremet ◽  
Claude Prigent ◽  
Amel Benammar Elgaaied
Keyword(s):  
Mitotic Spindle ◽  
Aurora A Kinase ◽  
Aurora A ◽  
Hek 293 ◽  
Von Hippel Lindau ◽  
Cell Extracts ◽  
Vhl Protein ◽  
The Stability

AbstractThe serine/threonin kinase Aurora A is an oncoprotein, whereas von Hippel-Lindau protein (pVHL) is a tumor suppressor protein. Both proteins have the same localization during mitosis: in the mitotic spindle and the centrosome. These two proteins also have common functions, such as the regulation of the cell cycle, the stability of the mitotic spindle and both intervene in the functioning of centrosomes. In this study we have analyzed the interaction between Aurora A and pVHL with immunoprecipitation and in vitro phosphorylation experiments. We have confirmed that the immunoprecipitation of pVHL from Hek 293 cell extracts were coupled with Aurora A. In addition, the interaction between the two proteins has been tested by analyzing the phosphorylation of pVHL in vitro by Aurora A. The results revealed that pVHL was phosphorylated by Aurora A. In conclusion, the study demonstrated that Aurora A interacts with and phosphorylates pVHL. Given the role of these two proteins in cell division as well as their status in cancer, this interaction requires further investigation.

scholarly journals A novel Aurora-A kinase inhibitor MLN8237 induces cytotoxicity and cell-cycle arrest in multiple myeloma

Blood ◽  
2010 ◽  
Vol 115 (25) ◽  
pp. 5202-5213 ◽  
Author(s):  
Güllü Görgün ◽  
Elisabetta Calabrese ◽  
Teru Hideshima ◽  
Jeffrey Ecsedy ◽  
Giulia Perrone ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Mitotic Spindle ◽  
Kinase Inhibitor ◽  
Phase 1 ◽  
Tumor Burden ◽  
Aurora A Kinase ◽  
Aurora A ◽  
Mitotic Kinase

Abstract Aurora-A is a mitotic kinase that regulates mitotic spindle formation and segregation. In multiple myeloma (MM), high Aurora-A gene expression has been correlated with centrosome amplification and proliferation; thus, inhibition of Aurora-A in MM may prove to be therapeutically beneficial. Here we assess the in vitro and in vivo anti-MM activity of MLN8237, a small-molecule Aurora-A kinase inhibitor. Treatment of cultured MM cells with MLN8237 results in mitotic spindle abnormalities, mitotic accumulation, as well as inhibition of cell proliferation through apoptosis and senescence. In addition, MLN8237 up-regulates p53 and tumor suppressor genes p21 and p27. Combining MLN8237 with dexamethasone, doxorubicin, or bortezomib induces synergistic/additive anti-MM activity in vitro. In vivo anti-MM activity of MLN8237 was confirmed using a xenograft-murine model of human-MM. Tumor burden was significantly reduced (P = .007) and overall survival was significantly increased (P < .005) in animals treated with 30 mg/kg MLN8237 for 21 days. Induction of apoptosis and cell death by MLN8237 were confirmed in tumor cells excised from treated animals by TdT-mediated dUTP nick end labeling assay. MLN8237 is currently in phase 1 and phase 2 clinical trials in patients with advanced malignancies, and our preclinical results suggest that MLN8237 may be a promising novel targeted therapy in MM.

Centrosome Aurora A gradient ensures single polarity axis in C. elegans embryos

2020 ◽  
Vol 48 (3) ◽  
pp. 1243-1253 ◽  
Author(s):  
Sukriti Kapoor ◽  
Sachin Kotak
Keyword(s):  
Symmetry Breaking ◽  
Cell Fate ◽  
Cell Cortex ◽  
Axis Formation ◽  
Aurora A Kinase ◽  
Aurora A ◽  
C Elegans ◽  
Cell Embryo ◽  
Polarity Establishment

Cellular asymmetries are vital for generating cell fate diversity during development and in stem cells. In the newly fertilized Caenorhabditis elegans embryo, centrosomes are responsible for polarity establishment, i.e. anterior–posterior body axis formation. The signal for polarity originates from the centrosomes and is transmitted to the cell cortex, where it disassembles the actomyosin network. This event leads to symmetry breaking and the establishment of distinct domains of evolutionarily conserved PAR proteins. However, the identity of an essential component that localizes to the centrosomes and promotes symmetry breaking was unknown. Recent work has uncovered that the loss of Aurora A kinase (AIR-1 in C. elegans and hereafter referred to as Aurora A) in the one-cell embryo disrupts stereotypical actomyosin-based cortical flows that occur at the time of polarity establishment. This misregulation of actomyosin flow dynamics results in the occurrence of two polarity axes. Notably, the role of Aurora A in ensuring a single polarity axis is independent of its well-established function in centrosome maturation. The mechanism by which Aurora A directs symmetry breaking is likely through direct regulation of Rho-dependent contractility. In this mini-review, we will discuss the unconventional role of Aurora A kinase in polarity establishment in C. elegans embryos and propose a refined model of centrosome-dependent symmetry breaking.

Role of the anconeus in the stability of a lateral ligament and common extensor origin–deficient elbow: an in vitro biomechanical study

2019 ◽  
Vol 28 (5) ◽  
pp. 974-981 ◽  
Author(s):  
Armin Badre ◽  
David T. Axford ◽  
Sara Banayan ◽  
James A. Johnson ◽  
Graham J.W. King
Keyword(s):  
Biomechanical Study ◽  
Lateral Ligament ◽  
The Stability

scholarly journals MLN8054, an Inhibitor of Aurora A Kinase, Induces Senescence in Human Tumor Cells Both In vitro and In vivo

2010 ◽  
Vol 8 (3) ◽  
pp. 373-384 ◽  
Author(s):  
Jessica J. Huck ◽  
Mengkun Zhang ◽  
Alice McDonald ◽  
Doug Bowman ◽  
Kara M. Hoar ◽  
...  
Keyword(s):  
Tumor Cells ◽  
Human Tumor ◽  
Aurora A Kinase ◽  
Aurora A ◽  
Human Tumor Cells

scholarly journals Postrecruitment Function of Yeast Med6 Protein during the Transcriptional Activation by Mediator Complex

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Gwang Sik Kim ◽  
Young Chul Lee
Keyword(s):  
Gene Expression ◽  
Reporter Gene ◽  
Transcriptional Activation ◽  
Reporter Gene Expression ◽  
Temperature Sensitive ◽  
Internal Deletion ◽  
Cell Extracts ◽  
Evolutionarily Conserved

Med6 protein (Med6p) is a hallmark component of evolutionarily conserved Mediator complexes, and the genuine role of Med6p in Mediator functions remains elusive. For the functional analysis ofSaccharomyces cerevisiaeMed6p (scMed6p), we generated a series of scMed6p mutants harboring a small internal deletion. Genetic analysis of these mutants revealed that three regions (amino acids 33–42 (Δ2), 125–134 (Δ5), and 157–166 (Δ6)) of scMed6p are required for cell viability and are located at highly conserved regions of Med6 homologs. Notably, the Med6p-Δ2 mutant was barely detectable in whole-cell extracts and purified Mediator, suggesting a loss of Mediator association and concurrent rapid degradation. Consistent with this, the recombinant forms of Med6p having these mutations partially (Δ2) restore or fail (Δ5 and Δ6) to restore in vitro transcriptional defects caused by temperature-sensitivemed6mutation. In an artificial recruitment assay, Mediator containing a LexA-fused wild-type Med6p or Med6p-Δ5 was recruited to thelexAoperator region with TBP and activated reporter gene expression. However, the recruitment of Mediator containing LexA-Med6p-Δ6 tolexAoperator region resulted in neither TBP recruitment nor reporter gene expression. This result demonstrates a pivotal role of Med6p in the postrecruitment function of Mediator, which is essential for transcriptional activation by Mediator.

scholarly journals Protein phosphatase 6 regulates mitotic spindle formation by controlling the T-loop phosphorylation state of Aurora A bound to its activator TPX2

2010 ◽  
Vol 191 (7) ◽  
pp. 1315-1332 ◽  
Author(s):  
Kang Zeng ◽  
Ricardo Nunes Bastos ◽  
Francis A. Barr ◽  
Ulrike Gruneberg
Keyword(s):  
Protein Phosphatase ◽  
Aurora A ◽  
Spindle Formation ◽  
Regulatory Subunits ◽  
Kinase Activation ◽  
Activator Proteins ◽  
Mitotic Kinase ◽  
General Importance ◽  
The Stability

Many protein kinases are activated by a conserved regulatory step involving T-loop phosphorylation. Although there is considerable focus on kinase activator proteins, the importance of specific T-loop phosphatases reversing kinase activation has been underappreciated. We find that the protein phosphatase 6 (PP6) holoenzyme is the major T-loop phosphatase for Aurora A, an essential mitotic kinase. Loss of PP6 function by depletion of catalytic or regulatory subunits interferes with spindle formation and chromosome alignment because of increased Aurora A activity. Aurora A T-loop phosphorylation and the stability of the Aurora A–TPX2 complex are increased in cells depleted of PP6 but not other phosphatases. Furthermore, purified PP6 acts as a T-loop phosphatase for Aurora A–TPX2 complexes in vitro, whereas catalytically inactive mutants cannot dephosphorylate Aurora A or rescue the PPP6C depletion phenotype. These results demonstrate a hitherto unappreciated role for PP6 as the T-loop phosphatase regulating Aurora A activity during spindle formation and suggest the general importance of this form of regulation.

scholarly journals HNRNPA2B1 promotes multiple myeloma progression by increasing AKT3 expression via m6A-dependent stabilization of ILF3 mRNA

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Fengjie Jiang ◽  
Xiaozhu Tang ◽  
Chao Tang ◽  
Zhen Hua ◽  
Mengying Ke ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Proliferation ◽  
Cellular Proliferation ◽  
Aberrant Expression ◽  
The Stability ◽  
Induced Apoptosis ◽  
Proliferation In Vitro

AbstractN6-methyladenosine (m6A) modification is the most prevalent modification in eukaryotic RNAs while accumulating studies suggest that m6A aberrant expression plays an important role in cancer. HNRNPA2B1 is a m6A reader which binds to nascent RNA and thus affects a perplexing array of RNA metabolism exquisitely. Despite unveiled facets that HNRNPA2B1 is deregulated in several tumors and facilitates tumor growth, a clear role of HNRNPA2B1 in multiple myeloma (MM) remains elusive. Herein, we analyzed the function and the regulatory mechanism of HNRNPA2B1 in MM. We found that HNRNPA2B1 was elevated in MM patients and negatively correlated with favorable prognosis. The depletion of HNRNPA2B1 in MM cells inhibited cell proliferation and induced apoptosis. On the contrary, the overexpression of HNRNPA2B1 promoted cell proliferation in vitro and in vivo. Mechanistic studies revealed that HNRNPA2B1 recognized the m6A sites of ILF3 and enhanced the stability of ILF3 mRNA transcripts, while AKT3 downregulation by siRNA abrogated the cellular proliferation induced by HNRNPA2B1 overexpression. Additionally, the expression of HNRNPA2B1, ILF3 and AKT3 was positively associated with each other in MM tissues tested by immunohistochemistry. In summary, our study highlights that HNRNPA2B1 potentially acts as a therapeutic target of MM through regulating AKT3 expression mediated by ILF3-dependent pattern.

scholarly journals The role of the 5′-flanking sequence of a human tRNAGlu gene in modulation of its transcriptional activity in vitro

1990 ◽  
Vol 272 (3) ◽  
pp. 797-803 ◽  
Author(s):  
E S Gonos ◽  
J P Goddard
Keyword(s):  
Transcriptional Activity ◽  
Potential Model ◽  
Trna Gene ◽  
Deletion Mutants ◽  
Wild Type ◽  
Flanking Sequence ◽  
Cell Extracts ◽  
Transcription In Vitro

The role of a tRNA-like structure within the 5′-flanking sequence of a human tRNA(Glu) gene in the modulation of its transcription in vitro by HeLa cell extracts has been investigated using several deletion mutants of a recombinant of the gene which lacked part or all of the tRNA-like structure. The transcriptional efficiency of four mutants was the same as that of the wild-type recombinant, two mutants had decreased transcriptional efficiency, one was more efficient, and one, lacking part of the 5′ intragenic control region, was inactive. Correlation of the transcriptional efficiencies with the position and the size of the 5′-flanking sequence that was deleted indicated that the tRNA-like structure may be deleted without loss of transcriptional efficiency. Current models for the modulation of tRNA gene transcription by the 5′-flanking sequence are assessed in the light of the results obtained, and a potential model is presented.

scholarly journals Constitutive regulation of mitochondrial morphology by Aurora A kinase depends on a predicted cryptic targeting sequence at the N-terminus

Open Biology ◽  
2018 ◽  
Vol 8 (6) ◽  
pp. 170272 ◽  
Author(s):  
Rhys Grant ◽  
Ahmed Abdelbaki ◽  
Alessia Bertoldi ◽  
Maria P. Gavilan ◽  
Jörg Mansfeld ◽  
...  
Keyword(s):  
Cancer Progression ◽  
Mitochondrial Fraction ◽  
Mitochondrial Morphology ◽  
Aurora A Kinase ◽  
Mitochondrial Network ◽  
Aurora A ◽  
Mitochondrial Targeting ◽  
Cell Extracts ◽  
N Terminus ◽  
Different Levels

Aurora A kinase (AURKA) is a major regulator of mitosis and an important driver of cancer progression. The roles of AURKA outside of mitosis, and how these might contribute to cancer progression, are not well understood. Here, we show that a fraction of cytoplasmic AURKA is associated with mitochondria, co-fractionating in cell extracts and interacting with mitochondrial proteins by reciprocal co-immunoprecipitation. We have also found that the dynamics of the mitochondrial network are sensitive to AURKA inhibition, depletion or overexpression. This can account for the different mitochondrial morphologies observed in RPE-1 and U2OS cell lines, which show very different levels of expression of AURKA. We identify the mitochondrial fraction of AURKA as influencing mitochondrial morphology, because an N-terminally truncated version of the kinase that does not localize to mitochondria does not affect the mitochondrial network. We identify a cryptic mitochondrial targeting sequence in the AURKA N-terminus and discuss how alternative conformations of the protein may influence its cytoplasmic fate.

Kallistatin Inhibits Endothelial Cell Proliferation, Migration and Adhesion in Vitro and Angiogenesis in the Ischemic Hindlimb of Rats

Hypertension ◽  
2000 ◽  
Vol 36 (suppl_1) ◽  
pp. 706-707
Author(s):  
Robert Q Miao ◽  
Jun Agata ◽  
Lee Chao ◽  
Julie Chao
Keyword(s):  
Cell Proliferation ◽  
Endothelial Cell ◽  
Gene Delivery ◽  
Fluorescent Protein ◽  
Regional Blood Flow ◽  
Endothelial Cell Proliferation ◽  
Hek 293

P76 Kallistatin is a serine proteinase inhibitor (serpin) which has multifunctions including regulation of tissue kallikrein activity, blood pressure, inflammation and neointima hyperplasia. In this study, we investigated the potential role of kallistatin in vascular biology by studying its effects on the proliferation, migration and adhesion of cultured primary human endothelial cells in vitro, and angiogenesis in the ischemic hindlimb of rats. Purified kallistatin significantly inhibits cultured endothelial cell proliferation, migration and adhesion induced by VEGF or bFGF. To further investigate the role of kallistatin in vascular growth in vivo, we prepared adenovirus carrying the human kallistatin gene under the control of the cytomegalovirus promoter/enhancer (Ad.CMV-cHKBP). Expression of recombinant human kallistatin in HEK 293 cells transfected with Ad.CMV-cHKBP was identified by a specific ELISA. The effect of adenovirus-mediated kallistatin gene delivery on angiogenesis was evaluated in a rat model of hindlimb ischemia. Adenovirus carrying the human kallistatin or green fluorescent protein (GFP) gene were injected locally into the ischemic adductor at the time of surgery. Histological and morphometric analysis at 14 days post injection showed that adenovirus-mediated kallistatin gene delivery significantly reduced capillary density in the ischemic muscle as compared to that of control rats injected with GFP. The anti-angiogenic effect of kallistatin was associated with reduced regional blood flow in the ischemic hindlimb measured by microsphere assays. Expression of human kallistatin was identified in the injected muscle and immunoreactive human kallistatin levels were measured in the muscle and in the circulation of rats following kallistatin gene delivery. These results demonstrate a novel role of kallistatin in the inhibition of angiogenesis and in vascular remodeling.

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