scholarly journals Murine CENP-F Regulates Centrosomal Microtubule Nucleation and Interacts with Hook2 at the Centrosome

2009 ◽  
Vol 20 (22) ◽  
pp. 4790-4803 ◽  
Author(s):  
Katherine L. Moynihan ◽  
Ryan Pooley ◽  
Paul M. Miller ◽  
Irina Kaverina ◽  
David M. Bader
Keyword(s):  
Protein Function ◽  
Structure And Function ◽  
The Novel ◽  
Yeast Two Hybrid ◽  
Cellular Functions ◽  
Binding Partner ◽  
Broad Array ◽  
Organizing Center ◽  
And Function ◽  
Two Hybrid

The microtubule (MT) network is essential in a broad spectrum of cellular functions. Many studies have linked CENP-F to MT-based activities as disruption of this protein leads to major changes in MT structure and function. Still, the basis of CENP-F regulation of the MT network remains elusive. Here, our studies reveal a novel and critical localization and role for CENP-F at the centrosome, the major MT organizing center (MTOC) of the cell. Using a yeast two-hybrid screen, we identify Hook2, a linker protein that is essential for regulation of the MT network at the centrosome, as a binding partner of CENP-F. With recently developed immunochemical reagents, we confirm this interaction and reveal the novel localization of CENP-F at the centrosome. Importantly, in this first report of CENP-F−/− cells, we demonstrate that ablation of CENP-F protein function eliminates MT repolymerization after standard nocodazole treatment. This inhibition of MT regrowth is centrosome specific because MT repolymerization is readily observed from the Golgi in CENP-F−/− cells. The centrosome-specific function of CENP-F in the regulation of MT growth is confirmed by expression of truncated CENP-F containing only the Hook2-binding domain. Furthermore, analysis of partially reconstituted MTOC asters in cells that escape complete repolymerization block shows that disruption of CENP-F function impacts MT nucleation and anchoring rather than promoting catastrophe. Our study reveals a major new localization and function of CENP-F at the centrosome that is likely to impact a broad array of MT-based actions in the cell.

scholarly journals Conserved Residues in the C-Terminal Domain Affect the Structure and Function of CYP38 in Arabidopsis

2021 ◽  
Vol 12 ◽  
Author(s):  
Lujing Shi ◽  
Lele Du ◽  
Jingru Wen ◽  
Xiumei Zong ◽  
Wene Zhao ◽  
...  
Keyword(s):  
Thylakoid Membrane ◽  
Structure And Function ◽  
Wild Type ◽  
Yeast Two Hybrid ◽  
Conserved Residues ◽  
Terminal Domain ◽  
Target Binding ◽  
And Function ◽  
Two Hybrid

Arabidopsis cyclophilin38 (CYP38) is a thylakoid lumen protein critial for PSII assembly and maintenance, and its C-terminal region serves as the target binding domain. We hypothesized that four conserved residues (R290, F294, Q372, and F374) in the C-terminal domain are critical for the structure and function of CYP38. In yeast two-hybrid and protein pull-down assays, CYP38s with single-sited mutations (R290A, F294A, Q372A, or F374A) did not interact with the CP47 E-loop as the wild-type CYP38. In contrast, CYP38 with the R290A/F294A/Q372A/F374A quadruple mutation could bind the CP47 E-loop. Gene transformation analysis showed that the quadruple mutation prevented CYP38 to efficiently complement the mutant phenotype of cyp38. The C-terminal domain half protein with the quadruple mutation, like the wild-type one, could interact with the N-terminal domain or the CP47 E-loop in vitro. The cyp38 plants expressing CYP38 with the quadruple mutation showed a similar BN-PAGE profile as cyp38, but distinct from the wild type. The CYP38 protein with the quadruple mutation associated with the thylakoid membrane less efficiently than the wild-type CYP38. We concluded that these four conserved residues are indispensable as changes of all these residues together resulted in a subtle conformational change of CYP38 and reduced its intramolecular N-C interaction and the ability to associate with the thylakoid membrane, thus impairing its function in chloroplast.

Cellular structure and function

2021 ◽  
pp. 1-104
Keyword(s):  
Plasma Membrane ◽  
Nucleic Acids ◽  
Cellular Structure ◽  
Structure And Function ◽  
The Body ◽  
Signalling Pathways ◽  
Cellular Functions ◽  
Pharmacological Agents ◽  
Intracellular Organelles ◽  
And Function

‘Cellular structure and function’ covers the roles, structures, and functions of the main four types of macromolecules of the human body, namely proteins, lipids, carbohydrates, and nucleic acids. For these macromolecules, the roles and types of each class are discussed (for proteins this includes their roles as structural proteins and enzymes and their kinetics; for lipids, the roles and types of lipid found in the body are considered; for carbohydrates, their roles including structural and metabolic are discussed; and the structure of nucleic acids is described). Then follows a description of the organization of the cell, including the plasma membrane and its components, and the intracellular organelles. Cell growth, division, and apoptosis are covered, as are the formation of gametes, and finally the principles of how cellular functions can be modulated by pharmacological agents through receptors and signalling pathways are discussed.

scholarly journals Tubulin Folding Cofactor TBCB is a Target of the Salmonella Effector Protein SseK1

2020 ◽  
Vol 21 (9) ◽  
pp. 3193 ◽  
Author(s):  
Juan Luis Araujo-Garrido ◽  
Fernando Baisón-Olmo ◽  
Joaquín Bernal-Bayard ◽  
Francisco Romero ◽  
Francisco Ramos-Morales
Keyword(s):  
Host Cell ◽  
Type Iii Secretion ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Yeast Two Hybrid ◽  
Microtubule Network ◽  
Binding Partner ◽  
Tubulin Binding ◽  
Serovar Typhimurium ◽  
Novel Target ◽  
Two Hybrid

Salmonella enterica serovar Typhimurium is a human and animal pathogen that uses type III secretion system effectors to manipulate the host cell and fulfill infection. SseK1 is a Salmonella effector with glycosyltransferase activity. We carried out a yeast two-hybrid screen and have identified tubulin-binding cofactor B (TBCB) as a new binding partner for this effector. SseK1 catalyzed the addition of N-acetylglucosamine to arginine on TBCB, and its expression promoted the stabilization of the microtubule cytoskeleton of HEK293T cells. The conserved Asp-x-Asp (DxD) motif that is essential for the activity of SseK1 was required for the binding and modification of TBCB and for the effect on the cytoskeleton. Our study has identified a novel target for SseK1 and suggests that this effector may have a role in the manipulation of the host cell microtubule network to provide a safe niche for this pathogen.

scholarly journals Reconstitution of the membrane protein OmpF into biomimetic block copolymer–phospholipid hybrid membranes

2016 ◽  
Vol 7 ◽  
pp. 881-892 ◽  
Author(s):  
Matthias Bieligmeyer ◽  
Franjo Artukovic ◽  
Stephan Nussberger ◽  
Thomas Hirth ◽  
Thomas Schiestel ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Membrane Protein ◽  
Protein Function ◽  
Transmembrane Proteins ◽  
Synthetic Polymer ◽  
Structure And Function ◽  
Membrane Thickness ◽  
Channel Conductance ◽  
Biomimetic Polymer ◽  
And Function

Structure and function of many transmembrane proteins are affected by their environment. In this respect, reconstitution of a membrane protein into a biomimetic polymer membrane can alter its function. To overcome this problem we used membranes formed by poly(1,4-isoprene-block-ethylene oxide) block copolymers blended with 1,2-diphytanoyl-sn-glycero-3-phosphocholine. By reconstituting the outer membrane protein OmpF from Escherichia coli into these membranes, we demonstrate functionality of this protein in biomimetic lipopolymer membranes, independent of the molecular weight of the block copolymers. At low voltages, the channel conductance of OmpF in 1 M KCl was around 2.3 nS. In line with these experiments, integration of OmpF was also revealed by impedance spectroscopy. Our results indicate that blending synthetic polymer membranes with phospholipids allows for the reconstitution of transmembrane proteins under preservation of protein function, independent of the membrane thickness.

Identification of a VPS33B-Binding Protein That Facilitates Alpha Granule Formation In Human Megakaryocytes and Platelets.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1444-1444
Author(s):  
Denisa Urban ◽  
Ling Li ◽  
James Wasmuth ◽  
Hilary Christensen ◽  
John Parkinson ◽  
...  
Keyword(s):  
Conflicts Of Interest ◽  
Human Platelets ◽  
Multiprotein Complex ◽  
Yeast Two Hybrid ◽  
Granule Formation ◽  
Reading Frame ◽  
Binding Partner ◽  
Library Screen ◽  
Two Hybrid ◽  
Granule Release

Abstract Abstract 1444 Human platelets contain α-granules, dense (δ-) granules and lysosomes that release their contents upon platelet activation. Platelet granule release is important for hemostasis, since patients with inherited granule defects have bleeding problems. α-granules are absent in the gray platelet and ARC syndromes, while deficient δ-granules are observed in isolation, in combination with α-granule deficiency, or as part of a syndrome in the Hermansky-Pudlak, Chediak-Higashi and Griscelli syndromes. The biogenesis of α-granules is poorly understood. Our laboratory has identified VPS33B as a central player in the formation of platelet α-granules. VPS33B has yet to be characterized in detail, however, its homolog VPS33A is known to be part of a multiprotein complex involved intracellular vesicle trafficking. Studies in our laboratory suggest that VPS33B is also part of a multiprotein complex. We performed a yeast two-hybrid library screen with VPS33B as bait and found another member of the complex: the unidentified gene product of chromosome 14 open reading frame 133 (C14orf133). Sequence analysis indicated this to be human VPS16B. Our studies show that VPS16B specifically binds to VPS33B but not its homologue, VPS33A. Furthermore, we show that VPS33B forms a distinct complex from that of its homologue VPS33A. VPS16B was found to co-localize with trans-Golgi, late endosome and α-granule markers in megakaryocytic Dami cells. Ongoing studies suggest that knockdown of VPS16B affects α-granule formation. We conclude that VPS16B, much like its binding partner VPS33B, plays a crucial role in megakaryocyte and platelet α-granule biogenesis. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Recent progress in research on molecular mechanisms of autophagy in the heart

2015 ◽  
Vol 308 (4) ◽  
pp. H259-H268 ◽  
Author(s):  
Yasuhiro Maejima ◽  
Yun Chen ◽  
Mitsuaki Isobe ◽  
Åsa B. Gustafsson ◽  
Richard N. Kitsis ◽  
...  
Keyword(s):  
Heart Disease ◽  
Molecular Mechanisms ◽  
Therapeutic Potential ◽  
Degradation Process ◽  
Structure And Function ◽  
Cellular Functions ◽  
Evolutionarily Conserved ◽  
And Function ◽  
Cellular Dysfunction

Dysregulation of autophagy, an evolutionarily conserved process for degradation of long-lived proteins and organelles, has been implicated in the pathogenesis of human disease. Recent research has uncovered pathways that control autophagy in the heart and molecular mechanisms by which alterations in this process affect cardiac structure and function. Although initially thought to be a nonselective degradation process, autophagy, as it has become increasingly clear, can exhibit specificity in the degradation of molecules and organelles, such as mitochondria. Furthermore, it has been shown that autophagy is involved in a wide variety of previously unrecognized cellular functions, such as cell death and metabolism. A growing body of evidence suggests that deviation from appropriate levels of autophagy causes cellular dysfunction and death, which in turn leads to heart disease. Here, we review recent advances in understanding the role of autophagy in heart disease, highlight unsolved issues, and discuss the therapeutic potential of modulating autophagy in heart disease.

scholarly journals Lexico-grammatical Analysis of AdaOkere Agbasimalo’s The Forest Dames

2018 ◽  
Vol 7 (6) ◽  
pp. 1
Author(s):  
Goodluck C. Kadiri ◽  
Asadu Emmanuela Uzoma ◽  
Joekin Ekwueme
Keyword(s):  
Civil War ◽  
Structure And Function ◽  
Analytical Tool ◽  
The Novel ◽  
Parts Of Speech ◽  
Code Mixing ◽  
Grammatical Analysis ◽  
Women And Children ◽  
Nigerian Civil War ◽  
And Function

The importance of language in literary discourse can never be over-emphasized. Halliday and Matthiessen (2014), in broad terms, contend that language is used to carry out interpersonal functions in speech and writing. Hence, literary writers use language creatively to communicate their intended messages to their readers. This study, therefore, explores the lexico-grammatical assessment of AdaOkere Agbasimalo’s The Forest Dames. The study aimed at identifying the prevalent linguistic tools deployed in the novel by the author, as a style index, for plot and theme developments. Also, to discuss logically how these tools contribute to project meanings in the novel. The study adopts Leech and Short’s checklist of linguistic and stylistic categories as its analytical tool. Data were extracted randomly from the novel and analyzed qualitatively at levels of lexis and structure using the checklist. The findings revealed that the authors deployed more of the major parts of speech; military registers; code mixing and switching and pidginized word/expressions to express the theme of hostility and futility of war. Also, at the grammatical level, sentences according to structure and function; inverted and elliptical sentences; adverbial and adjectival clauses were also used to expresses various themes and to develop the plots of the novel logically. It was concluded that Agbasimalo is a writer who used English creatively to express the consequences of Nigerian civil war on women and children. Conversely, it was suggested that scholars should conduct further studies on other aspects not covered in this research.

scholarly journals Motivos clásicos en la novela Distintas formas de mirar el agua de Julio Llamazares

2018 ◽  
pp. 41
Author(s):  
Álida Ares Ares
Keyword(s):  
Structure And Function ◽  
The Novel ◽  
Classical Literature ◽  
Thematic Content ◽  
Landscape Features ◽  
And Function ◽  
Julio Llamazares

<p>En este artículo se analiza la novela de Julio Llamazares Distintas formas de mirar el agua (2015)1 estudiando los elementos característicos de la obra que guardan semejanza con los trenos y plantos del teatro griego. Para ello, en primer lugar, se señalan las similitudes en lo que se refiere a la estructura y a la función de los personajes, así como el contenido temático y los tópicos clásicos del género elegíaco. A continuación, se consideran las distintas funciones del paisaje en la literatura clásica, subrayando los paralelismos y los valores que este adquiere en la novela. Para concluir se hace una breve reflexión acerca del concepto ideológico de tragedia que se refleja en el drama contemporáneo y en la obra del autor.</p><p><br />This article analyzes the novel written by Julio Llamazares, Distintas formas de mirar el agua (2015), and takes into account characteristic elements of the work that are reminiscent of Greek Theatre threnodies (planto or treno). In order to do this, we underline in the first place the similarities linked to the structure and function of the characters and also the thematic content and topics of elegiac classical genre. Then we consider various landscape features in classical literature emphasizing parallels and values that it acquires in this novel. In conclusion, we make a brief consideration about the ideological concept of tragedy reflected in contemporary drama and in this work of Llamazares.</p>

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