scholarly journals Membrane Shape Remodeling by Protein Crowding

2020 ◽  
Author(s):  
Susanne Liese ◽  
Andreas Carlson
Keyword(s):  
Spontaneous Curvature ◽  
Steric Repulsion ◽  
Membrane Tension ◽  
Wide Range ◽  
Associated Proteins ◽  
Protein Crowding ◽  
Membrane Shape ◽  
Flat Membranes ◽  
Spherical Vesicles ◽  
Shape Changes

AbstractThe steric repulsion between proteins on biological membranes is one of the most generic mechanisms that cause membrane shape changes. We present a minimal model where a spontaneous curvature is induced by steric repulsion between membrane-associated proteins. Our results show that the interplay between the induced spontaneous curvature and the membrane tension determine the energy minimizing shapes, which describe the wide range of experimentally observed membrane shapes, i.e. flat membranes, spherical vesicles, elongated tubular protrusions, and pearling structures.

scholarly journals Use of Proteins Identified through a Functional Genomic Screen To Develop a Protein Subunit Vaccine That Provides Significant Protection against Virulent Streptococcus suis in Pigs

2017 ◽  
Vol 86 (3) ◽  
Author(s):  
Susan L. Brockmeier ◽  
Crystal L. Loving ◽  
Tracy L. Nicholson ◽  
Jinhong Wang ◽  
Sarah E. Peters ◽  
...  
Keyword(s):  
Immune Response ◽  
Vaccine Trial ◽  
Streptococcus Suis ◽  
Protein Subunit ◽  
Content Type ◽  
Degree Of Protection ◽  
Wide Range ◽  
Associated Proteins ◽  
Clinical Protection ◽  
Cellular Immune

ABSTRACT Streptococcus suis is a bacterium that is commonly carried in the respiratory tract and that is also one of the most important invasive pathogens of swine, commonly causing meningitis, arthritis, and septicemia. Due to the existence of many serotypes and a wide range of immune evasion capabilities, efficacious vaccines are not readily available. The selection of S. suis protein candidates for inclusion in a vaccine was accomplished by identifying fitness genes through a functional genomics screen and selecting conserved predicted surface-associated proteins. Five candidate proteins were selected for evaluation in a vaccine trial and administered both intranasally and intramuscularly with one of two different adjuvant formulations. Clinical protection was evaluated by subsequent intranasal challenge with virulent S. suis . While subunit vaccination with the S. suis proteins induced IgG antibodies to each individual protein and a cellular immune response to the pool of proteins and provided substantial protection from challenge with virulent S. suis , the immune response elicited and the degree of protection were dependent on the parenteral adjuvant given. Subunit vaccination induced IgG reactive against different S. suis serotypes, indicating a potential for cross protection.

A dominant inhibitory version of the small GTP-binding protein Rac disrupts cytoskeletal structures and inhibits developmental cell shape changes in Drosophila

Development ◽  
1995 ◽  
Vol 121 (3) ◽  
pp. 903-914 ◽  
Author(s):  
N. Harden ◽  
H.Y. Loh ◽  
W. Chia ◽  
L. Lim
Keyword(s):  
Epidermal Cell ◽  
Cell Shape ◽  
Shape Change ◽  
Yeast Cells ◽  
Cell Shape Change ◽  
Gtp Binding ◽  
Wide Range ◽  
Cell Shape Changes ◽  
Germband Retraction ◽  
Shape Changes

The Rho subfamily of Ras-related small GTP-binding proteins is involved in regulation of the cytoskeleton. The cytoskeletal changes induced by two members of this subfamily, Rho and Rac, in response to growth factor stimulation, have dramatic effects on cell morphology. We are interested in using Drosophila as a system for studying how such effects participate in development. We have identified two Drosophila genes, DRacA and DRacB, encoding proteins with homology to mammalian Rac1 and Rac2. We have made transgenic flies bearing dominant inhibitory (N17DRacA), and wild-type versions of the DRacA cDNA under control of an Hsp70 promoter. Expression of the N17DRacA transgene during embryonic development causes a high frequency of defects in dorsal closure which are due to disruption of cell shape changes in the lateral epidermis. Embryonic expression of N17DRacA also affects germband retraction and head involution. The epidermal cell shape defects caused by expression of N17DRacA are accompanied by disruption of a localized accumulation of actin and myosin thought to be driving epidermal cell shape change. Thus the Rho subfamily may be generating localized changes in the cytoskeleton during Drosophila development in a similar fashion to that seen in mammalian and yeast cells. The Rho subfamily is likely to be participating in a wide range of developmental processes in Drosophila through its regulation of the cytoskeleton.

Paucimyces polynucleatus gen. nov, sp. nov., a novel polycentric genus of anaerobic gut fungi from the faeces of a wild blackbuck antelope

2021 ◽  
Vol 71 (6) ◽  
Author(s):  
Radwa A. Hanafy ◽  
Noha H. Youssef ◽  
Mostafa S. Elshahed
Keyword(s):  
Ribosomal Subunit ◽  
New Genus And Species ◽  
Isolation And Characterization ◽  
Faecal Samples ◽  
Wide Range ◽  
Culture Independent ◽  
Antilope Cervicapra ◽  
Spherical Vesicles ◽  
Sequence Similarities

The anaerobic gut fungi (AGF; phylum Neocallimastigomycota) reside in the alimentary tracts of herbivores. Multiple novel, yet-uncultured AGF taxa have recently been identified in culture-independent diversity surveys. Here, we report on the isolation and characterization of the first representative of the RH5 lineage from faecal samples of a wild blackbuck (Indian Antelope, Antilope cervicapra) from Sutton County, Texas, USA. The isolates displayed medium sized (2–4 mm) compact circular colonies on agar roll tubes and thin loose biofilm-like growth in liquid medium. Microscopic examination revealed monoflagellated zoospores and polycentric thalli with highly branched nucleated filamentous rhizomycelium, a growth pattern encountered in a minority of described AGF genera so far. The obtained isolates are characterized by formation of spherical vesicles at the hyphal tips from which multiple sporangia formed either directly on the spherical vesicles or at the end of sporangiophores. Phylogenetic analysis using the D1/D2 regions of the large ribosomal subunit (D1/D2 LSU) and the ribosomal internal transcribed spacer 1 (ITS1) revealed sequence similarities of 93.5 and 81.3%, respectively, to the closest cultured relatives (Orpinomyces joyonii strain D3A (D1/D2 LSU) and Joblinomyces apicalis strain GFH681 (ITS1). Substrate utilization experiments using the type strain (BB-3T) demonstrated growth capabilities on a wide range of mono-, oligo- and polysaccharides, including glucose, xylose, mannose, fructose, cellobiose, sucrose, maltose, trehalose, lactose, cellulose, xylan, starch and raffinose. We propose accommodating these novel isolates in a new genus and species, for which the name Paucimyces polynucleatus gen. nov., sp. nov. is proposed.

Functional Contacts With a Range of Splicing Proteins Suggest a Central Role for Brr2p in the Dynamic Control of the Order of Events in Spliceosomes ofSaccharomyces cerevisiae

Genetics ◽  
2001 ◽  
Vol 157 (4) ◽  
pp. 1451-1467 ◽  
Author(s):  
Rob W van Nues ◽  
Jean D Beggs
Keyword(s):  
Protein Interactions ◽  
Dynamic Control ◽  
Splicing Factors ◽  
Functional Protein ◽  
U6 Snrna ◽  
Wide Range ◽  
Snrnp Protein ◽  
Associated Proteins ◽  
Step Factor ◽  
Hybrid Screening

AbstractMapping of functional protein interactions will help in understanding conformational rearrangements that occur within large complexes like spliceosomes. Because the U5 snRNP plays a central role in pre-mRNA splicing, we undertook exhaustive two-hybrid screening with Brr2p, Prp8p, and other U5 snRNP-associated proteins. DExH-box protein Brr2p interacted specifically with five splicing factors: Prp8p, DEAH-box protein Prp16p, U1 snRNP protein Snp1p, second-step factor Slu7p, and U4/U6.U5 tri-snRNP protein Snu66p, which is required for splicing at low temperatures. Co-immunoprecipitation experiments confirmed direct or indirect interactions of Prp16p, Prp8p, Snu66p, and Snp1p with Brr2p and led us to propose that Brr2p mediates the recruitment of Prp16p to the spliceosome. We provide evidence that the prp8-1 allele disrupts an interaction with Brr2p, and we propose that Prp8p modulates U4/U6 snRNA duplex unwinding through another interaction with Brr2p. The interactions of Brr2p with a wide range of proteins suggest a particular function for the C-terminal half, bringing forward the hypothesis that, apart from U4/U6 duplex unwinding, Brr2p promotes other RNA rearrangements, acting synergistically with other spliceosomal proteins, including the structurally related Prp2p and Prp16p. Overall, these protein interaction studies shed light on how splicing factors regulate the order of events in the large spliceosome complex.

scholarly journals Evaluation by quantitative acid elution and radioimmunoassay of multiple classes of immunoglobulins and serum albumin associated with platelets in idiopathic thrombocytopenic purpura

Blood ◽  
1986 ◽  
Vol 67 (4) ◽  
pp. 1126-1131 ◽  
Author(s):  
AJ Hotchkiss ◽  
CA Leissinger ◽  
ME Smith ◽  
JV Jordan ◽  
CA Kautz ◽  
...  
Keyword(s):  
Serum Albumin ◽  
Idiopathic Thrombocytopenic Purpura ◽  
Solid Phase ◽  
Similar Group ◽  
Thrombocytopenic Purpura ◽  
Large Numbers ◽  
Wide Range ◽  
Platelet Concentration ◽  
Associated Proteins ◽  
Solid Phase Radioimmunoassay

Abstract Immunoglobulins (Igs) and serum albumin were eluted from normal platelets and platelets from patients with idiopathic thrombocytopenic purpura (ITP) with a quantitative acid elution procedure followed by solid-phase radioimmunoassay (SPRIA). Acid elution was shown to release a reproducible fraction of platelet-associated Igs, and the amounts released per platelet were independent of the platelet concentration over a wide range of concentrations. This procedure is suitable for sensitive, reproducible, and specific quantitation of large numbers of samples. Washed platelets from 13 normal donors contained the following components (expressed in femtograms per platelet, mean +/- 2 SEM): IgG, 1.40 +/- 0.26; IgA, 0.72 +/- 0.36; IgM 0.078 +/- 0.036; albumin 7.7 +/- 1.5. Immunoglobulins and albumin eluted from the platelets of ten ITP patients (two in remission), expressed as femtograms per platelet, mean (range), were: IgG 104 (0.3 to 750); IgA 90 (0.9 to 715); IgM 162 (1.2 to 1,300); and albumin 34 (6.8 to 199). All platelet-associated Igs from thrombocytopenic ITP patients were found to be elevated twofold to 2,300-fold with one Ig class occasionally elevated 50-fold to 100-fold higher than the others. A similar group of ten thrombocytopenic ITP patients was found to have twofold to 26-fold elevations of platelet- associated albumin. This demonstration of increases in multiple classes of Igs as well as serum albumin associated with platelets from ITP patients suggests that some nonimmune process may be contributing to the phenomenon of increased platelet-associated proteins in ITP.

scholarly journals The structured core of human β tubulin confers isotype-specific polymerization properties

2016 ◽  
Vol 213 (4) ◽  
pp. 425-433 ◽  
Author(s):  
Melissa C. Pamula ◽  
Shih-Chieh Ti ◽  
Tarun M. Kapoor
Keyword(s):  
Dynamic Instability ◽  
Sequence Divergence ◽  
Regulatory Proteins ◽  
Microtubule Dynamic ◽  
Microtubule Associated Proteins ◽  
Cytoskeleton Organization ◽  
Wide Range ◽  
Associated Proteins ◽  
And Function ◽  
Β Tubulin

Diversity in cytoskeleton organization and function may be achieved through variations in primary sequence of tubulin isotypes. Recently, isotype functional diversity has been linked to a “tubulin code” in which the C-terminal tail, a region of substantial sequence divergence between isotypes, specifies interactions with microtubule-associated proteins. However, it is not known whether residue changes in this region alter microtubule dynamic instability. Here, we examine recombinant tubulin with human β isotype IIB and characterize polymerization dynamics. Microtubules with βIIB have catastrophe frequencies approximately threefold lower than those with isotype βIII, a suppression similar to that achieved by regulatory proteins. Further, we generate chimeric β tubulins with native tail sequences swapped between isotypes. These chimeras have catastrophe frequencies similar to that of the corresponding full-length construct with the same core sequence. Together, our data indicate that residue changes within the conserved β tubulin core are largely responsible for the observed isotype-specific changes in dynamic instability parameters and tune tubulin’s polymerization properties across a wide range.

scholarly journals Regulation of the Postsynaptic Compartment of Excitatory Synapses by the Actin Cytoskeleton in Health and Its Disruption in Disease

2016 ◽  
Vol 2016 ◽  
pp. 1-19 ◽  
Author(s):  
Holly Stefen ◽  
Chanchanok Chaichim ◽  
John Power ◽  
Thomas Fath
Keyword(s):  
Actin Cytoskeleton ◽  
Neurological Diseases ◽  
Synaptic Function ◽  
Excitatory Synapses ◽  
Key Factors ◽  
Complex Interplay ◽  
Structure And Dynamics ◽  
Wide Range ◽  
Associated Proteins ◽  
Cytoskeletal Elements

Disruption of synaptic function at excitatory synapses is one of the earliest pathological changes seen in wide range of neurological diseases. The proper control of the segregation of neurotransmitter receptors at these synapses is directly correlated with the intact regulation of the postsynaptic cytoskeleton. In this review, we are discussing key factors that regulate the structure and dynamics of the actin cytoskeleton, the major cytoskeletal building block that supports the postsynaptic compartment. Special attention is given to the complex interplay of actin-associated proteins that are found in the synaptic specialization. We then discuss our current understanding of how disruption of these cytoskeletal elements may contribute to the pathological events observed in the nervous system under disease conditions with a particular focus on Alzheimer’s disease pathology.

The subtype I-F CRISPR–Cas system influences pathogenicity island retention in Pectobacterium atrosepticum via crRNA generation and Csy complex formation

2013 ◽  
Vol 41 (6) ◽  
pp. 1468-1474 ◽  
Author(s):  
Corinna Richter ◽  
Peter C. Fineran
Keyword(s):  
Complex Formation ◽  
Large Scale ◽  
Protein Complexes ◽  
Acquired Resistance ◽  
Mobile Genetic Elements ◽  
Bacterial Evolution ◽  
Pectobacterium Atrosepticum ◽  
Crispr System ◽  
Wide Range ◽  
Associated Proteins

CRISPR (clustered regularly interspaced short palindromic repeats) arrays and Cas (CRISPR-associated) proteins confer acquired resistance against mobile genetic elements in a wide range of bacteria and archaea. The phytopathogen Pectobacterium atrosepticum SCRI1043 encodes a single subtype I-F CRISPR system, which is composed of three CRISPR arrays and the cas operon encoding Cas1, Cas3 (a Cas2–Cas3 fusion), Csy1, Csy2, Csy3 and Cas6f (Csy4). The CRISPR arrays are transcribed into pre-crRNA (CRISPR RNA) and then processed by Cas6f to generate crRNAs. Furthermore, the formation of Cas protein complexes has been implicated in both the interference and acquisition stages of defence. In the present paper, we discuss the development of tightly controlled ‘programmable’ CRISPR arrays as tools to investigate CRISPR–Cas function and the effects of chromosomal targeting. Finally, we address how chromosomal targeting by CRISPR–Cas can cause large-scale genome deletions, which can ultimately influence bacterial evolution and pathogenicity.

scholarly journals Theoretical Study of N-Heterocyclic-Carbene–ZnX2 (X = H, Me, Et) Complexes

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6147
Author(s):  
Mirosław Jabłoński
Keyword(s):  
Theoretical Study ◽  
Twist Angle ◽  
Steric Effects ◽  
Torsional Angle ◽  
Steric Repulsion ◽  
Hydrogen Atoms ◽  
Wide Range ◽  
The Relationship ◽  
Tetrel Bonds ◽  
Negligible Influence

This article discusses the properties of as many as 30 carbene–ZnX2 (X = H, Me, Et) complexes featuring a zinc bond C⋯Zn. The group of carbenes is represented by imidazol-2-ylidene and its nine derivatives (labeled as IR), in which both hydrogen atoms of N-H bonds have been substituted by R groups with various spatial hindrances, from the smallest Me, iPr, tBu through Ph, Tol, and Xyl to the bulkiest Mes, Dipp, and Ad. The main goal is to study the relationship between type and size of R and X and both the strength of C⋯Zn and the torsional angle of the ZnX2 plane with respect to the plane of the imidazol-2-ylidene ring. Despite the considerable diversity of R and X, the range of dC⋯Zn is quite narrow: 2.12–2.20 Å. On the contrary, D0 is characterized by a fairly wide range of 18.5–27.4 kcal/mol. For the smallest carbenes, the ZnX2 molecule is either in the plane of the carbene or is only slightly twisted with respect to it. The twist angle becomes larger and more varied with the bulkier R. However, the value of this angle is not easy to predict because it results not only from the presence of steric effects but also from the possible presence of various interatomic interactions, such as dihydrogen bonds, tetrel bonds, agostic bonds, and hydrogen bonds. It has been shown that at least some of these interactions may have a non-negligible influence on the structure of the IR–ZnX2 complex. This fact should be taken into account in addition to the commonly discussed R⋯X steric repulsion.

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