6,071 research outputs found
Regulation of EGF receptor trafficking by the lysine deacetylase HDAC6
No full textEpidermal growth factor (EGF) receptor belongs to the broad family of enzymatic receptors called receptor tyrosine kinases (RTKs). Generally, the binding of a ligand to these receptors leads to activation of their intracellular kinase activity that sets in motion a cascade of signaling events. In order to ensure appropriate responses to physiological stimuli, the cell is endowed with the ability to regulate signal transduction via numerous mechanisms such as dephosphorylation of the RTK and its substrates as well as downregulation of the RTK. Activation of EGFR is a potent mitogenic (proliferative) and motogenic (cell motility) signal that plays crucial roles during embryonic development and maintenance of adult tissue. EGFR signaling is primarily regulated by ligand-induced receptor internalization with subsequent degradation in lysosomes. While the complex of proteins that are recruited to EGFR after its activation is well understood, proteins that interact with the receptor in the absence of ligand binding are still not systematically studied. With the goal of identifying novel binding partners of non-activated EGFR, a membrane based yeast-two hybrid screen (MYTH) was conducted. MYTH is based on the principle of in vivo reconstitution of the N-terminus (Nub) and C-terminus (Cub) halves of ubiquitin once brought into close proximity. A chimeric protein consisting of EGFR fused to Cub and a transcription factor was used as a bait to screen Nub-tagged cDNA library. Analysis of resultant yeast transformants revealed a total of 87 proteins to interact with EGFR. Of these only 11 were previously shown to bind to EGFR. A majority of the other proteins were shown to interact with the receptor by yeast retransformation. Fifteen were confirmed to bind to EGFR by coimmunoprecipitation assays in mammalian cells. One of the novel EGFR interactors identified in the screen was histone deacetylase 6 (HDAC6). This deacetylase is localized in the cytoplasm and known to deacetylate alpha-tubulin, HSP90 and cortactin. The juxtamembrane region of EGFR binds to the Cterminus of HDAC6. Functionally, overexpression of wild type HDAC6 stabilized ligand-induced degradation of the receptor. On the other hand, deacetylase deficient or EGFR binding compromised mutants of HDAC6 were able to stabilize EGFR only partially. Downmodulation of HDAC6 expression by RNAi markedly accelerated degradation of the receptor. Taken together, HDAC6 is a negative regulator of EGFR downregulation that is dependent on its deacetylase activity and ability to bind to the receptor. Imaging studies revealed that HDAC6 does not affect internalization of EGFR from the plasma membrane but rather influences the post-endocytic trafficking of the receptor-ligand complex to lysosomes. Pulse-chase experiments using fluorophoretagged EGF showed that EGFR is transported faster towards the peri-nuclear region and delivered to late endosomes rapidly in HDAC6 depleted cells. HDAC6 is demonstrated to act, at least partly, by regulating the acetylation of alpha-tubulin. Upon EGFR activation, acetylation of alpha-tubulin on lysine 40 is progressively increased as shown by mass spectrometry and immunoblotting. Forced expression of a dominant negative mutant of alpha-tubulin, but not wild type alpha-tubulin, led to reduced speed and processive movement of early endosomes in GFP-Rab5 expressing cells. In a surprising twist, EGFR is able to phosphorylate HDAC6 on Tyr570. Phosphorylation of Tyr570 and Ser568 leads to inactivation of the deacetylase function of HDAC6 as shown by in vivo and in vitro assays. In summary, HDAC6 diminishes EGFR downregulation by slowing the transport of intracellular vesicles. The inhibitory effect is removed once HDAC6 is phosphorylated on key residues. In line with these findings, two recent reports have shown that hyper-acetylation of alpha-tubulin induced by inhibition of HDAC6 increases the transport of brain derived neurotrophic factor and JNK interacting protein-1 in different cell systems. Acetylated microtubules are more efficient in recruiting motor proteins like kinesin-1 and dynein. These findings indicate that HDAC6 plays an important regulatory role in intracellular trafficking pathways. However, several outstanding issues still remain unresolved. How does acetylation of microtubules influence vesicular trafficking? In this regard, the temporal and spatial dynamics of alpha-tubulin acetylation following EGFR activation should be studied. Furthermore, whether HDAC6 affects the trafficking of other endocytic cargos and additional organelles is an interesting question to address.Der epidermale Wachstumsfaktor-Rezeptor (EGFR) gehört zu der umfassenden Familie enzymatisch aktiver Rezeptoren, die als Rezeptortyrosinkinasen (RTKs) bezeichnet werden. RTKs stellen eine große Gruppe der Zelloberflächenrezeptoren dar, die eine intrinsische Tyrosinkinaseaktivität aufweisen. Sie katalysieren infolge extrazellulärer Stimuli den Transfer der gamma-Phosphatgruppe eines ATP-Moleküls auf Hydroxylgruppen von Tyrosinresten3. Die allgemeine Struktur von RTKs lässt sich in eine extrazelluläre Ligandenbindedomäne, eine einzige Transmembrandomäne und eine zytoplasmatische, katalytisch aktive Region gliedern, auf die der für die Regulation der Signalweiterleitung verantwortliche C-Terminus folgt. Die Bindung eines Liganden an diese Rezeptoren führt im allgemeinen zur Aktivierung ihrer intrazellulären Kinaseaktivität, die eine Kaskade von Signalvorgängen in Gang setzt. Im Fall des EGFR bindet der Ligand (EGF) als Monomer an den Rezeptor in einem Verhältnis von 2:2 und induziert Konformationsänderungen, die zur Dimerisierung des Rezeptors führen. Daraufhin werden Signalwege innerhalb der Zelle eingeleitet, indem Proteine, die eine Phosphotyrosinbindedomäne aufweisen, an phosporylierte Tyrosinreste im Cterminalen Bereich des Rezeptors binden. Die Aktivität des EGFR sowie anderer RTKs ist streng reguliert, um eine angemessene und physiologische Antwort auf einen Stimulus zu generieren. Mehrere Mechanismen wie die Dephosphorylierung des Rezeptors und weiterer Komponenten des Signalweges stellen sicher, dass die Signalweiterleitung entsprechend beendet wird. Der wichtigste Mechanismus, um die Weiterleitung des Signals herunterzuregulieren, besteht jedoch in der schnellen Endozytose und dem anschließendem Abbau sowohl des Rezeptors als auch des Liganden. Die Aktivierung infolge der Bindung eines Liganden führt zur Anhäufung des Rezeptors in von Clathrin überzogenen Einstülpungen (CCPs) auf der Plasmamembran, die sich anschließend durch Bildung von „Clathrin bedeckten Vesikeln“ (CCVs) abschnüren. Der EGFR wird über CCVs, frühe Endosomen und multivesikuläre Körper schließlich zum Abbau ins Lysosom gebracht. Das Schicksal der Fracht entscheidet sich auf der Ebene des frühen Endosoms: entweder kommt es zur Rückführung an die Plasmamembran oder zum Abbau im Lysosom. Welcher Weg eingeschlagen wird, hängt von der Ubiquitinierung der Fracht ab, die von einem Proteinkomplex (endosomal-sorting complex required for transport (ESCRT)) erkannt wird. Mikrotubuli und die an diese assoziierten Motorproteine wie Dynein sind für den Transport früher Endosomen zu späten Endosomen essentiell und somit auch für den Abbau der Fracht. In der vorliegenden Doktorarbeit wurde ein modifizierter membrane yeast two-hybrid screen (MYTH) durchgeführt, um neue Interaktionspartner des Liganden-unbesetzten, inaktiven EGFR zu identifizieren. Das Prinzip des MYTH besteht auf dem splitubiquitin System, wobei ein “quasi natives Ubiquitinmolekül” rekonstituiert wird, wenn die N-terminale und C-terminale Hälfte des Ubiquitinmoleküls (Nub bzw. Cub) in einer Zelle separat exprimiert werden. Ein Transmembranprotein, an das Cub fusioniert ist, kann dabei als Köder benutzt werden, um eine cDNA library, die an Nub gekoppelt vorliegt, auf neue Bindungspartner hin zu untersuchen. Einer der in dem Screen neu identifizierten EGFR-Bindungspartner ist die Histondeacetylase 6 (HDAC6). HDAC6 ist eine einzigartige Deacetylase, die aus zwei katalytischen Domänen und einer Ubiquitin-bindenden Zinkfingerdomäne besteht und fast ausschließlich im Zytoplasma lokalisiert ist. Dadurch, dass sie -Tubulin deacetyliert, spielt HDAC6 u. a. eine wichtige Rolle bei der chemotaktisch induzierten Zellmotilität, der Fusion des HIV-1 Viruspartikels mit der Zellmembran sowie der Bildung von Immunsynapsen. HDAC6 sorgt auch für die Aufrechterhaltung des richtigen Acetylierungsgrades von HSP90, der für die Interaktion mit seinen Ko-Chaperonen und weiteren Assoziationspartnern benötigt wird. Unabhängig von ihrer Deacetylaseaktivität dient HDAC6 durch Bindung an polyubiquitinierte Proteine einerseits und Dynein andererseits als Adaptorprotein. Diese Rolle von HDAC6 ist für die Beseitigung falsch gefalteter Proteine und Aggresomen von Bedeutung. Das Hauptziel dieser Doktorarbeit ist die Identifizierung neuer EGFR Bindungspartner, die an den inaktiven Rezeptor gebunden sind, sowie die funktionelle Charakterisierung putativer Interaktionspartner
Kevin Brockmeier, Fiction Reading
No full textOctober 25, 2013, Ulrich Museum of Art, Wichita State UniversityAward winning author Kevin Brockmeier, reads from his work.University Libraries, Department of English, Department of Women's Studies, Watermark Books & Cafe, Ulrich Museum of Ar
Dr. Kevin Pelletier – Faculty Author Interview
No full textDr. Kevin Pelletier, Associate Professor of English, discusses his new book, Apocalyptic Sentimentalism: Love and Fear in US Antebellum Literature, published recently by the University of Georgia Press. The book provides powerful insights into the relationship between nineteenth-century sentimentality, religious discourse, and antislavery reform
Kevin Fenton: A Reading
No full textThe John S. Lucas Great River Reading Series (GRRS) hosts Winona native and author Kevin Fenton. Fenton will read from his new novel Cyan Magenta Yellow Black published by Black Lawrence Press, 2025.
Kevin Fenton is the author of Merit Badges, which won the AWP Prize for the Novel and the Friends of the American Writers Award, and Leaving Rollingstone, which Patricia Hampl called “the most important memoir to come out of the Midwest (or anywhere) in years.” He works as an advertising writer and creative director; in that capacity, he’s published essays in the design quarterlies Émigré and Eye (London), the anthology Looking Closer 2: Critical Writing On Graphic Design, and the UX design blog Boxes and Arrows. He got a slightly better education than he deserved at Beloit College, the University of Minnesota Law School, and the University of Minnesota MFA program. He lives in St Paul with his wife Ellen and his greyhound Evie
'Web of Life' - Profile of Kevin Petrie in Printmaking Today Winter 2024
No full textKevin Petrie, Professor of Creative Practice at the University of Sunderland, uses print to explore the novels and philosophy of Iris Murdoch writes Dr Miles Leeson. This is a 1200 word profile of Kevin Petrie and his recent work for 'Printmaking Today' which is the journal of the Royal Society of Painter Printmakers. The piece gives an overview of Petrie's creative practice focusing on the novels and thinking of Dame Iris Murdoch (1919-1999). The piece discusses Petrie's evolving model of creative practice for this project: reading the novels, sketching to visualise elements, developing and combining images in the studio and then reengagement with Murdoch (through the community, literature and archive). Petrie's 'Other Journeys' and 'Web of Life' exhibitions are discussed.
The author, Dr Miles Leeson, is the Director of the Iris Murdoch Research Centre at University of Chichester and Visiting Research Fellow at Kingston University. He is the lead editor of the Iris Murdoch Review, the Series Editor of ‘Iris Murdoch Today’ with Palgrave Macmillan, and has published widely on Murdoch’s work. He published Iris Murdoch: Philosophical Novelist (Continuum) in 2010, the edited collection Incest in Contemporary Literature (Manchester University Press, 2018), the festschrift Iris Murdoch: A Centenary Celebration (Sabrestorm Fiction, 2019), the edited collection Iris Murdoch and the Literary Imagination (Palgrave Macmillan, 2022) and is currently writing Iris Murdoch: Feminist.
Four prints by Kevin Petrie are reproduced with the text:
Untangle
2024
Etching from two plates with Chine Collé
Paper 38x29cm Image 14.8x12.5cm
Photo: Dave Williams
Friends
2023
Etching with Chine Collé
Paper 38x29cm Image 14.8x12.5cm
Photo: Dave Williams
Love
2023
Etching with Chine Collé
Paper 38x29cm Image 14.8x12.5cm
Photo: Dave Williams
What lies beneath
2024
Lithograph
38.5x28cm
Printed by Lee Turner at Hole Editions Newcastle
Photo: Dave William
Dr. Kevin Cherry – Faculty Author Interview
No full textDr. Kevin Cherry, Assistant Professor of Political Science,discusses his new book, Plato, Aristotle, and the Purpose of Politics, published recently by Cambridge University Press. In this book, he compares the views of Plato and Aristotle about the practice, study and the purpose of politics
Dr. Kevin Cruz - Faculty Author Interview
No full textDr. Kevin Cruz, Assistant Professor of Management in the Robins School of Business, discusses his recent article, “Perceptions of psychological contract breach and perceptions of co-worker exclusion: The moderating effects of collectivism and individualism,” in Occupational Health Science. Dr. Cruz’s research interests focus on employee – employer relationships, employee – team relationships and employee – co-worker relationships
Major, Kevin
No full textThe fonds consists of records created and received by Kevin Major as a Canadian writer, editor and teacher between 1974 and 2014. Material includes correspondence with family, friends, writers, editors, agents and readers; contracts and royalty statements; material related to author readings and appearances at literary festivals; school visits and other author appearances; literary awards received by the author; literary awards juries the author participated in; as well as general media coverage about the author. The fonds contains materials related to each of the author’s published works, including administrative documents, research, manuscript drafts and media coverage. The fonds also includes documentation about the author’s personal life, including materials related to his education, his teaching career, travel, and family life.
The types of documents include letters and e-mails, transcripts, posters, contracts, reports, research notes, manuscripts, certificates, books, newspapers and journals, photographs, slides, interviews, and audio/visual materials in a variety of media: cassette tapes, CDs, CD-ROMs, DVDs and VHS tapes
Barer, Julie & Wilson, Kevin : Publishing Panel; November 26th, 2018
No full textContents:
All tracks Panel [complete]
Track 01 Introduction
Track 02 Q&A
Digital Projects SAN: folder location for wav and mp3 files: /J:\Elliston Working\11-27-2018 (Julie Barer and Kevin Wilson
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