scholarly journals Virus membrane-fusion proteins: more than one way to make a hairpin

2006 ◽  
Vol 4 (1) ◽  
pp. 67-76 ◽  
Author(s):  
Margaret Kielian ◽  
Félix A. Rey
Keyword(s):  
Membrane Fusion ◽  
Fusion Proteins ◽  
Membrane Fusion Proteins

scholarly journals Interdependent assembly of specific regulatory lipids and membrane fusion proteins into the vertex ring domain of docked vacuoles

2004 ◽  
Vol 167 (6) ◽  
pp. 1087-1098 ◽  
Author(s):  
Rutilio A. Fratti ◽  
Youngsoo Jun ◽  
Alexey J. Merz ◽  
Nathan Margolis ◽  
William Wickner
Keyword(s):  
Membrane Fusion ◽  
Protein Interactions ◽  
Fusion Proteins ◽  
Membrane Microdomains ◽  
Rab Gtpase ◽  
Protein Protein Interactions ◽  
Px Domain ◽  
Protein Partitioning ◽  
Membrane Fusion Proteins ◽  
Rab Effector

Membrane microdomains are assembled by lipid partitioning (e.g., rafts) or by protein–protein interactions (e.g., coated vesicles). During docking, yeast vacuoles assemble “vertex” ring-shaped microdomains around the periphery of their apposed membranes. Vertices are selectively enriched in the Rab GTPase Ypt7p, the homotypic fusion and vacuole protein sorting complex (HOPS)–VpsC Rab effector complex, SNAREs, and actin. Membrane fusion initiates at vertex microdomains. We now find that the “regulatory lipids” ergosterol, diacylglycerol and 3- and 4-phosphoinositides accumulate at vertices in a mutually interdependent manner. Regulatory lipids are also required for the vertex enrichment of SNAREs, Ypt7p, and HOPS. Conversely, SNAREs and actin regulate phosphatidylinositol 3-phosphate vertex enrichment. Though the PX domain of the SNARE Vam7p has direct affinity for only 3-phosphoinositides, all the regulatory lipids which are needed for vertex assembly affect Vam7p association with vacuoles. Thus, the assembly of the vacuole vertex ring microdomain arises from interdependent lipid and protein partitioning and binding rather than either lipid partitioning or protein interactions alone.

scholarly journals Membrane Fusion Proteins Are Required for oskar mRNA Localization in the Drosophila Egg Chamber

2000 ◽  
Vol 218 (2) ◽  
pp. 314-325 ◽  
Author(s):  
Douglas M Ruden ◽  
Vincent Sollars ◽  
Xiaoyan Wang ◽  
Daisuke Mori ◽  
Marina Alterman ◽  
...  
Keyword(s):  
Membrane Fusion ◽  
Fusion Proteins ◽  
Mrna Localization ◽  
Egg Chamber ◽  
Membrane Fusion Proteins

Development of New Cloning Vectors for the Production of Immunogenic Outer Membrane Fusion Proteins in Escherichia coli

1996 ◽  
Vol 14 (2) ◽  
pp. 203-208 ◽  
Author(s):  
Pierre Cornells ◽  
Javier Cote Sierra ◽  
Antonio Lim ◽  
Achut Malur ◽  
Sumalee Tungpradabkul ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Membrane Fusion ◽  
Outer Membrane ◽  
Fusion Proteins ◽  
Cloning Vectors ◽  
Membrane Fusion Proteins

scholarly journals Identification and Characterization of TriABC-OpmH, a Triclosan Efflux Pump of Pseudomonas aeruginosa Requiring Two Membrane Fusion Proteins

2007 ◽  
Vol 189 (21) ◽  
pp. 7600-7609 ◽  
Author(s):  
Takehiko Mima ◽  
Swati Joshi ◽  
Margarita Gomez-Escalada ◽  
Herbert P. Schweizer
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Membrane Fusion ◽  
Fusion Proteins ◽  
Efflux Pump ◽  
Divalent Cations ◽  
Constitutive Expression ◽  
Multiple Copies ◽  
High Level ◽  
Triclosan Resistance ◽  
Membrane Fusion Proteins

ABSTRACT Pseudomonas aeruginosa achieves high-level (MIC > 1 mg/ml) triclosan resistance either by constitutive expression of MexAB-OprM, an efflux pump of the resistance nodulation cell division (RND) family, or expression of MexCD-OprJ, MexEF-OprN, and MexJK-OpmH in regulatory mutants. A triclosan-resistant target enzyme and perhaps other mechanisms probably act synergistically with efflux. To probe this notion, we exposed the susceptible Δ(mexAB-oprM) Δ(mexCD-oprJ) Δ(mexEF-oprN) Δ(mexJK) Δ(mexXY) strain PAO509 to increasing triclosan concentrations and derived a resistant strain, PAO509.5. This mutant overexpressed the PA0156-PA0157-PA0158 pump, which only effluxed triclosan, but not closely related compounds, antibiotics, and divalent cations, and was therefore renamed TriABC. Constitutive expression of the triABC operon was due to a single promoter-up mutation. Deletion of two adjacent genes, pcaR and PA0159, encoding transcriptional regulators had no effect on expression of this operon. TriABC is the only P. aeruginosa RND pump which contains two membrane fusion proteins, TriA and TriB, and both are required for efflux pump function. Probably owing to tight transcriptional coupling of the triABC genes, complementation of individual mutations was only partially achievable. Full complementation was only observed when a complete triABC operon was provided in trans, either in single or multiple copies. TriABC associated with OpmH, but not OprM, for assembly of a functional triclosan efflux pump. TriABC is the fifth RND pump in P. aeruginosa shown to efficiently efflux triclosan, supporting the notion that efflux is the primary mechanism responsible for this bacterium's high intrinsic and acquired triclosan resistance.

scholarly journals Fusogenic Reoviruses and Their Fusion-Associated Small Transmembrane (FAST) Proteins

2019 ◽  
Vol 6 (1) ◽  
pp. 341-363 ◽  
Author(s):  
Roy Duncan
Keyword(s):  
Membrane Fusion ◽  
Fusion Proteins ◽  
Syncytium Formation ◽  
Nonstructural Proteins ◽  
Enveloped Virus ◽  
Fast Proteins ◽  
Nonenveloped Virus ◽  
Functional Features ◽  
Membrane Fusion Proteins ◽  
Viral Membrane Fusion

With no limiting membrane surrounding virions, nonenveloped viruses have no need for membrane fusion to gain access to intracellular replication compartments. Consequently, nonenveloped viruses do not encode membrane fusion proteins. The only exception to this dogma is the fusogenic reoviruses that encode fusion-associated small transmembrane (FAST) proteins that induce syncytium formation. FAST proteins are the smallest viral membrane fusion proteins and, unlike their enveloped virus counterparts, are nonstructural proteins that evolved specifically to induce cell-to-cell, not virus-cell, membrane fusion. This distinct evolutionary imperative is reflected in structural and functional features that distinguish this singular family of viral fusogens from all other protein fusogens. These rudimentary fusogens comprise specific combinations of different membrane effector motifs assembled into small, modular membrane fusogens. FAST proteins offer a minimalist model to better understand the ubiquitous process of protein-mediated membrane fusion and to reveal novel mechanisms of nonenveloped virus dissemination that contribute to virulence.

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