scholarly journals A cationic motif in Engrailed-2 homeoprotein controls its internalization via selective cell-surface glycosaminoglycans interactions

2021 ◽  
Author(s):  
Sebastien CARDON ◽  
Gerard BOLBACH ◽  
Yadira P HERVIS ◽  
Chrystel LOPIN-BON ◽  
Jean-Claude JACQUINET ◽  
...  
Keyword(s):  
Cell Surface ◽  
Critical Role ◽  
Amino Acid Level ◽  
Cationic Protein ◽  
Intrinsically Disordered ◽  
Structure And Dynamics ◽  
Internalization Mechanism ◽  
Initial Interaction ◽  
Basic Region

Engrailed-2 (En2) is a transcription factor that possesses as most homeoproteins the unique and intriguing property to transfer from cell to cell through unconventional pathways. The internalization mechanism of this cationic protein is far from being fully understood and is proposed to require an initial interaction with cell-surface glycosaminoglycans (GAGs). To decipher the role of GAGs in the recognition of En2 at the cell surface, we have quantified the internalization of the homeodomain region in cell lines that differ in their content in cell-surface GAGs. The binding specificity to GAGs and the influence of this interaction on the structure and dynamics of En2 was also investigated at the amino acid level. Our results show that a high-affinity GAG-binding hexadecapeptide (RKPKKKNPNKEDKRPR) located upstream of the homeodomain controls internalization efficiency of En2 through selective interactions with highly-sulfated GAGs of heparan sulfate type. Our data underline the functional importance of the intrinsically disordered basic region that precedes the prominent internalization domain in En2, and demonstrate the critical role of GAGs as an entry gate for En2, finely tuning its capacity to internalize into cells.

Critical role of the C-terminal segment in the maturation and export to the cell surface of the homopentameric alpha7-5HT3A receptor

2004 ◽  
Vol 20 (8) ◽  
pp. 2022-2030 ◽  
Author(s):  
S. Pons ◽  
J. Sallette ◽  
J. P. Bourgeois ◽  
A. Taly ◽  
J. P. Changeux ◽  
...  
Keyword(s):  
Cell Surface ◽  
Critical Role ◽  
Terminal Segment

scholarly journals ENL initiates multivalent phase separation of the super elongation complex (SEC) in controlling rapid transcriptional activation

2020 ◽  
Vol 6 (14) ◽  
pp. eaay4858 ◽  
Author(s):  
Chenghao Guo ◽  
Zhuanzhuan Che ◽  
Junjie Yue ◽  
Peng Xie ◽  
Shaohua Hao ◽  
...  
Keyword(s):  
Phase Separation ◽  
Rna Polymerase Ii ◽  
Transcriptional Activation ◽  
Liquid Droplet ◽  
Critical Role ◽  
Elongation Factor ◽  
Elongation Complex ◽  
Intrinsically Disordered ◽  
Super Elongation Complex

Release of paused RNA polymerase II (Pol II) requires incorporation of the positive transcription elongation factor b (P-TEFb) into the super elongation complex (SEC), thus resulting in rapid yet synchronous transcriptional activation. However, the mechanism underlying dynamic transition of P-TEFb from inactive to active state remains unclear. Here, we found that the SEC components are able to compartmentalize and concentrate P-TEFb via liquid-liquid phase separation from the soluble inactive HEXIM1 containing the P-TEFb complex. Specifically, ENL or its intrinsically disordered region is sufficient to initiate the liquid droplet formation of SEC. AFF4 functions together with ENL in fluidizing SEC droplets. SEC droplets are fast and dynamically formed upon serum exposure and required for rapid transcriptional induction. We also found that the fusion of ENL with MLL can boost SEC phase separation. In summary, our results suggest a critical role of multivalent phase separation of SEC in controlling transcriptional pause release.

scholarly journals Cell surface protease activation during RAS transformation: Critical role of the plasminogen receptor, S100A10

Oncotarget ◽  
2016 ◽  
Vol 7 (30) ◽  
pp. 47720-47737 ◽  
Author(s):  
Patricia A. Madureira ◽  
Alamelu G. Bharadwaj ◽  
Moamen Bydoun ◽  
Katy Garant ◽  
Paul O'Connell ◽  
...  
Keyword(s):  
Cell Surface ◽  
Critical Role ◽  
Protease Activation ◽  
Cell Surface Protease

scholarly journals Experimental Evidence of Intrinsic Disorder and Amyloid Formation by the Henipavirus W Proteins

2022 ◽  
Vol 23 (2) ◽  
pp. 923
Author(s):  
Giulia Pesce ◽  
Frank Gondelaud ◽  
Denis Ptchelkine ◽  
Juliet F. Nilsson ◽  
Christophe Bignon ◽  
...  
Keyword(s):  
Phase Separation ◽  
Critical Role ◽  
Limited Proteolysis ◽  
Size Exclusion ◽  
Amyloid Formation ◽  
Type I ◽  
Human Pathogens ◽  
Intrinsically Disordered ◽  
P Gene

Henipaviruses are severe human pathogens within the Paramyxoviridae family. Beyond the P protein, the Henipavirus P gene also encodes the V and W proteins which share with P their N-terminal, intrinsically disordered domain (NTD) and possess a unique C-terminal domain. Henipavirus W proteins antagonize interferon (IFN) signaling through NTD-mediated binding to STAT1 and STAT4, and prevent type I IFN expression and production of chemokines. Structural and molecular information on Henipavirus W proteins is lacking. By combining various bioinformatic approaches, we herein show that the Henipaviruses W proteins are predicted to be prevalently disordered and yet to contain short order-prone segments. Using limited proteolysis, differential scanning fluorimetry, analytical size exclusion chromatography, far-UV circular dichroism and small-angle X-ray scattering, we experimentally confirmed their overall disordered nature. In addition, using Congo red and Thioflavin T binding assays and negative-staining transmission electron microscopy, we show that the W proteins phase separate to form amyloid-like fibrils. The present study provides an additional example, among the few reported so far, of a viral protein forming amyloid-like fibrils, therefore significantly contributing to enlarge our currently limited knowledge of viral amyloids. In light of the critical role of the Henipavirus W proteins in evading the host innate immune response and of the functional role of phase separation in biology, these studies provide a conceptual asset to further investigate the functional impact of the phase separation abilities of the W proteins.

scholarly journals The Intrinsically Disordered W Protein Is Multifunctional during Henipavirus Infection, Disrupting Host Signalling Pathways and Nuclear Import

Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1913
Author(s):  
Sofiya Tsimbalyuk ◽  
Emily M. Cross ◽  
Mikayla Hoad ◽  
Camilla M. Donnelly ◽  
Justin A. Roby ◽  
...  
Keyword(s):  
Specific Binding ◽  
Critical Role ◽  
Innate Immune ◽  
Host Protein ◽  
Host Cells ◽  
Signalling Pathways ◽  
Multiple Functions ◽  
Intrinsically Disordered ◽  
P Gene

Nipah and Hendra viruses are highly pathogenic, zoonotic henipaviruses that encode proteins that inhibit the host’s innate immune response. The W protein is one of four products encoded from the P gene and binds a number of host proteins to regulate signalling pathways. The W protein is intrinsically disordered, a structural attribute that contributes to its diverse host protein interactions. Here, we review the role of W in innate immune suppression through inhibition of both pattern recognition receptor (PRR) pathways and interferon (IFN)-responsive signalling. PRR stimulation leading to activation of IRF-3 and IFN release is blocked by henipavirus W, and unphosphorylated STAT proteins are sequestered within the nucleus of host cells by W, thereby inhibiting the induction of IFN stimulated genes. We examine the critical role of nuclear transport in multiple functions of W and how specific binding of importin-alpha (Impα) isoforms, and the 14-3-3 group of regulatory proteins suggests further modulation of these processes. Overall, the disordered nature and multiple functions of W warrant further investigation to understand henipavirus pathogenesis and may reveal insights aiding the development of novel therapeutics.

scholarly journals Critical Role of Serine 465 in Isoflurane-induced Increase of Cell-surface Redistribution and Activity of Glutamate Transporter Type 3

2006 ◽  
Vol 281 (50) ◽  
pp. 38133-38138 ◽  
Author(s):  
Yueming Huang ◽  
Xiaorong Feng ◽  
Julianne J. Sando ◽  
Zhiyi Zuo
Keyword(s):  
Cell Surface ◽  
Critical Role ◽  
Glutamate Transporter ◽  
Type 3

scholarly journals Linking protein structure and dynamics to catalysis: the role of hydrogen tunnelling

2006 ◽  
Vol 361 (1472) ◽  
pp. 1323-1331 ◽  
Author(s):  
Judith P Klinman
Keyword(s):  
Critical Role ◽  
Heavy Atom ◽  
Hydrogen Atom Transfer ◽  
Transfer Reactions ◽  
Structure And Dynamics ◽  
Alternate Model ◽  
Reaction Barriers ◽  
Hydrogen Isotope Effect ◽  
The Impact

Early studies of enzyme-catalysed hydride transfer reactions indicated kinetic anomalies that were initially interpreted in the context of a ‘tunnelling correction’. An alternate model for tunnelling emerged following studies of the hydrogen atom transfer catalysed by the enzyme soybean lipoxygenase. This invokes full tunnelling of all isotopes of hydrogen, with reaction barriers reflecting the heavy atom, environmental reorganization terms. Using the latter approach, we offer an integration of the aggregate data implicating hydrogen tunnelling in enzymes (i.e. deviations from Swain–Schaad relationships and the semi-classical temperature dependence of the hydrogen isotope effect). The impact of site-specific mutations of enzymes plays a critical role in our understanding of the factors that control tunnelling in enzyme reactions.

scholarly journals CRITICAL ROLE OF DETERMINANT PRESENTATION IN THE INDUCTION OF SPECIFIC RESPONSES IN IMMUNO-COMPETENT LYMPHOCYTES

1973 ◽  
Vol 137 (4) ◽  
pp. 967-990 ◽  
Author(s):  
David H. Katz ◽  
Emil R. Unanue
Keyword(s):  
T Cells ◽  
B Cells ◽  
T Lymphocytes ◽  
Cell Surface ◽  
Critical Role ◽  
Antibody Responses ◽  
Soluble Antigen ◽  
Protein Conjugates

A detailed analysis of the role of determinant presentation in the process of triggering immunocompetent lymphocytes has been made utilizing cell-bound hapten-carrier conjugates to elicit secondary antihapten antibody responses, primarily in vitro. The results of these experiments demonstrate that: (a) hapten-protein conjugates will attach to the surface membranes of macrophages directly, in the absence of specific antibodies, in a highly immunogenic form; (b) such macrophage-bound conjugates serve as remarkedly efficient stimuli to trigger both thymus-derived (T) and bone marrow-derived (B) cells in a specific manner, lowering the optimal threshold antigen dose (in molar terms) by several logs as compared with soluble antigen; (c) the macrophage is not unique in this regard, since fibroblasts are essentially comparable in the capacity to present antigen in highly immunogenic form; (d) cell surface-bound antigen clearly favors secondary in vitro responses of the IgG as compared with the IgM antibody class; (e) in terms of triggering B or T cells, antigen bound to macrophages in the form of immune complexes does not appear to possess any appreciable advantage over equimolar quantities of directly attached antigen; (f) the increased immunogenicity of cell-bound antigen appears to reflect certain crucial, and undefined, features of cell surface membranes and not merely the stabilization of determinants on a relatively immobile surface; and (g) although the efficiency of lymphocyte triggering is markedly enhanced by cell-bound antigen, the presence of macrophages is apparently not an absolute requirement for eliciting secondary in vitro antibody responses to soluble hapten-protein conjugates. The relevance of these observations to the nature of the signal induced upon antigen interaction by specific lymphocytes and the sequential cellular events involved in the regulatory influence of activated T cells on B cell responses to antigen is discussed. We postulate that T lymphocytes are best triggered by cell-bound antigen and that after this step the activated T lymphocytes regulate the triggering of B cells with antigen.

Sign in / Sign up

Export Citation Format

Share Document