Functional Recognition of Bacterial Mitogens by Reactive B Lymphocytes Related to Membrane Protein Composition

1987 ◽  
pp. 87-99
Author(s):  
Bernhard Kleine ◽  
Lothar Biesert ◽  
Ingeborg Dölker ◽  
Raimund Sprenger ◽  
Hans-Martin Vordermeier ◽  
...  
Keyword(s):  
Membrane Protein ◽  
B Lymphocytes ◽  
Protein Composition

Outer Membrane Protein Composition in Disease Isolates of Haemophilus influenzae : Pathogenic and Epidemiological Implications

1980 ◽  
Vol 30 (3) ◽  
pp. 709-717
Author(s):  
Marilyn R. Loeb ◽  
David H. Smith
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Haemophilus Influenzae ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Outer Membrane Proteins ◽  
Protein Composition ◽  
The Other ◽  
Major Protein ◽  
Single Strain

The outer membrane protein composition of 50 disease isolates of Haemophilus influenzae has been determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. All strains, including 28 strains of serotype b , one strain each of serotypes a, c, d, e , and f , and 17 untypable strains, had an outer membrane protein composition typical of gram-negative bacteria, i.e., these membranes contained two to three dozen proteins with four to six proteins accounting for most of their protein content. Variation in the mobility of these major outer membrane proteins from strain to strain was common but not universal; the observed patterns provided useful data and new insight into the epidemiology of type b disease. The basic findings can be summarized as follows: (i) All 50 strains possessed three proteins (one minor and two major) each having identical mobilities. The other proteins, both major and minor, varied in mobility. (ii) All type b strains possessed a fourth (major) protein of identical mobility. (iii) The 28 type b strains, on the basis of the mobility of the six major outer membrane proteins, could be divided into eight subtypes. Of all the other strains examined, both typable and untypable, only the serotype a strain belonged to one of these subtypes. (iv) The untypable strains showed considerable variation in the mobilities of their major outer membrane proteins. Of these 17 strains, 13 had an additional major outer membrane protein not present in encapsulated strains. (v) The outer membrane protein composition of a single strain remained unchanged after many passages on solid media, but varied with the growth phase. (vi) The outer membrane protein composition of isolates obtained from nine patients during an epidemic of type b meningitis varied, indicating that a single strain was not responsible for the epidemic. At least five different strains were responsible for these nine cases. (vii) Identical outer membrane protein compositions were observed in the following: in a type b strain and a mutant of this strain deficient in capsule production, indicating that the level of capsule synthesis is not obviously related to outer membrane protein composition; in type b strains isolated from different anatomic sites of patients acutely ill with meningitis, indicating that the strain associated with bacteremia is the same as that isolated from the cerebrospinal fluid; in type b strains isolated from siblings who contracted meningitis at about the same time, indicating infection with the same strain; and in type b strains isolated from the initial and repeat infection of a single patient, suggesting that reinfection was due to the same strain.

scholarly journals THIS ARTICLE HAS BEEN RETRACTED Epstein-Barr virus-encoded latent membrane protein 1 activates β-catenin signaling in B lymphocytes

2009 ◽  
Vol 100 (5) ◽  
pp. 807-812 ◽  
Author(s):  
Mariko Tomita ◽  
Md. Zahidunnabi Dewan ◽  
Naoki Yamamoto ◽  
Akira Kikuchi ◽  
Naoki Mori
Keyword(s):  
Membrane Protein ◽  
B Lymphocytes ◽  
Epstein Barr Virus ◽  
Latent Membrane Protein ◽  
Latent Membrane Protein 1 ◽  
Barr Virus ◽  
Epstein Barr

Altered erythrocyte membrane protein composition mirrors pleiotropic effects of hypertension susceptibility genes and disease pathogenesis

2015 ◽  
Vol 33 (11) ◽  
pp. 2265-2277 ◽  
Author(s):  
Alexey V. Polonikov ◽  
Dmitry V. Ushachev ◽  
Vladimir P. Ivanov ◽  
Mikhail I. Churnosov ◽  
Maxim B. Freidin ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Erythrocyte Membrane ◽  
Protein Composition ◽  
Susceptibility Genes ◽  
Pleiotropic Effects ◽  
Disease Pathogenesis ◽  
Erythrocyte Membrane Protein

scholarly journals The ner Gene of Photorhabdus: Effects on Primary-Form-Specific Phenotypes and Outer Membrane Protein Composition

2002 ◽  
Vol 184 (14) ◽  
pp. 4048-4048
Author(s):  
Keith H. O'Neill ◽  
Declan M. Roche ◽  
David J. Clarke ◽  
Barbara C. A. Dowds
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Protein Composition ◽  
Primary Form

scholarly journals impA, a Gene Coding for an Inner Membrane Protein, Influences Colonial Morphology of Actinobacillus actinomycetemcomitans

2000 ◽  
Vol 68 (12) ◽  
pp. 6580-6586 ◽  
Author(s):  
Keith P. Mintz ◽  
Paula M. Fives-Taylor
Keyword(s):  
Membrane Protein ◽  
Protein Composition ◽  
Protein S ◽  
Actinobacillus Actinomycetemcomitans ◽  
Conjugative Plasmid ◽  
Inverse Pcr ◽  
Adherent Cell ◽  
Inner Membrane ◽  
Gene Coding ◽  
Inner Membrane Protein

ABSTRACT Directed mutagenesis of a gene coding for a membrane protein of the periodontopathogen Actinobacillus actinomycetemcomitans was achieved by conjugation. The gene was disrupted by insertion of an antibiotic cassette into a unique endonuclease restriction sequence engineered by inverse PCR. The disrupted gene was cloned into a conjugative plasmid and transferred from Escherichia colito A. actinomycetemcomitans. The allelic replacement mutation resulted in the loss of a 22-kDa inner membrane protein. The loss of this protein (ImpA) resulted in changes in the outer membrane protein composition of the bacterium. Concurrent with the mutation in impA was a change in the pattern of growth of the mutant bacteria in broth cultures. The progenitor bacteria grew as a homogeneous suspension of cells compared to a granular, autoaggregating adherent cell population described for the mutant bacteria. These data suggest that ImpA may play a regulatory role or be directly involved in protein(s) that are exported and associated with colony variations in A. actinomycetemcomitans.

scholarly journals Latent Membrane Protein 2A-Mediated Effects on the Phosphatidylinositol 3-Kinase/Akt Pathway

2000 ◽  
Vol 74 (22) ◽  
pp. 10838-10845 ◽  
Author(s):  
Rachel Swart ◽  
Ingrid K. Ruf ◽  
Jeffery Sample ◽  
Richard Longnecker
Keyword(s):  
Membrane Protein ◽  
B Cell ◽  
Cell Survival ◽  
B Lymphocytes ◽  
Latent Membrane Protein ◽  
Phosphatidylinositol 3 Kinase ◽  
Latent Membrane Protein 2A ◽  
Amino Terminal ◽  
B Cell Survival ◽  
Phosphatidylinositol 3

ABSTRACT Epstein-Barr virus (EBV) latent membrane protein 2A (LMP2A) is expressed on the membranes of B lymphocytes and blocks B-cell receptor (BCR) signaling in EBV-transformed B lymphocytes in vitro. The phosphotyrosine motifs at positions 74 or 85 and 112 within the LMP2A amino-terminal domain are essential for the LMP2A-mediated block of B-cell signal transduction. In vivo studies indicate that LMP2A allows B-cell survival in the absence of normal BCR signals. A possible role for Akt in the LMP2A-mediated B-cell survival was investigated. The protein kinase Akt is a crucial regulator of cell survival and is activated within B lymphocytes upon BCR cross-linking. LMP2A expression resulted in the constitutive phosphorylation of Akt, and this LMP2A effect is dependent on phosphatidylinositol 3-kinase activity. In addition, recruitment of Syk and Lyn protein tyrosine kinases (PTKs) to tyrosines 74 or 85 and 112, respectively, are critical for LMP2A-mediated Akt phosphorylation. However, the ability of LMP2A to mediate a survival phenotype downstream of Akt could not be detected in EBV-negative Akata cells. This would indicate that LMP2A is not responsible for EBV-dependent Burkitt's lymphoma cell survival.

scholarly journals Parkin-mediated ubiquitination contributes to the constitutive turnover of mitochondrial fission factor (Mff)

2019 ◽  
Author(s):  
Laura Lee ◽  
Richard Seager ◽  
Kevin A. Wilkinson ◽  
Jeremy M. Henley
Keyword(s):  
Membrane Protein ◽  
Ubiquitin Ligase ◽  
Mitochondrial Membrane ◽  
Mitochondrial Fission ◽  
Protein Composition ◽  
Mitochondrial Outer Membrane ◽  
Dependent Manner ◽  
Mitochondrial Network ◽  
Functionally Impaired ◽  
Mitochondrial Membrane Protein

AbstractThe mitochondrial outer membrane protein Mitochondrial Fission Factor (Mff) plays a key role in both physiological and pathological fission. It is well established that in stressed or functionally impaired mitochondria the PINK1 recruits the ubiquitin ligase Parkin which ubiquitinates Mff to facilitate the removal of defective mitochondria and maintain the integrity mitochondrial network. Here we show that, in addition to this clearance pathway, Parkin also ubiquitinates Mff in a PINK1-dependent manner under basal, non-stressed conditions to regulate constitutive Mff turnover. We further show that removing Parkin with shRNA knockdown does not completely prevent Mff ubiquitination under these conditions indicating that at least one other ubiquitin ligase contributes to Mff proteostasis. These data demonstrate that Parkin plays a role in physiological maintenance of mitochondrial membrane protein composition in healthy mitochondria through constitutive low-level activation.

scholarly journals APEX2 proximity proteomics resolves flagellum subdomains and identifies flagellum tip-specific proteins in Trypanosoma brucei

2020 ◽  
Author(s):  
Daniel E. Vélez-Ramírez ◽  
Michelle M. Shimogawa ◽  
Sunayan Ray ◽  
Andrew Lopez ◽  
Shima Rayatpisheh ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Trypanosoma Brucei ◽  
Model Organism ◽  
Protein Composition ◽  
Principal Component ◽  
Protozoan Parasite ◽  
Sleeping Sickness ◽  
Critical Gap ◽  
Flagellar Membrane ◽  
And Function

ABSTRACTTrypanosoma brucei is the protozoan parasite responsible for sleeping sickness, a lethal vector-borne disease. T. brucei has a single flagellum that plays critical roles in parasite biology, transmission and pathogenesis. An emerging concept in flagellum biology is that the organelle is organized into subdomains, each having specialized composition and function. Overall flagellum proteome has been well-studied, but a critical gap in knowledge is the protein composition of individual flagellum subdomains. We have therefore used APEX-based proximity proteomics to examine protein composition of T. brucei flagellum subdomains. To assess effectiveness of APEX-based proximity labeling, we fused APEX2 to the DRC1 subunit of the nexin-dynein regulatory complex, an axonemal complex distributed along the flagellum. We found that DRC1-APEX2 directs flagellum-specific biotinylation and purification of biotinylated proteins yields a DRC1 “proximity proteome” showing good overlap with proteomes obtained from purified axonemes. We next employed APEX2 fused to a flagellar membrane protein that is restricted to the flagellum tip, adenylate cyclase 1 (AC1), or a flagellar membrane protein that is excluded from the flagellum tip, FS179. Principal component analysis demonstrated the pools of biotinylated proteins in AC1-APEX2 and FS179-APEX2 samples are distinguished from each other. Comparing proteins in these two pools allowed us to identify an AC1 proximity proteome that is enriched for flagellum tip proteins and includes several proteins involved in signal transduction. Our combined results demonstrate that APEX2-based proximity proteomics is effective in T. brucei and can be used to resolve proteome composition of flagellum subdomains that cannot themselves be readily purified.IMPORTANCESleeping sickness is a neglected tropical disease, caused by the protozoan parasite Trypanosoma brucei. The disease disrupts the sleep-wake cycle, leading to coma and death if left untreated. T. brucei motility, transmission, and virulence depend on its flagellum (aka cilium), which consists of several different specialized subdomains. Given the essential and multifunctional role of the T. brucei flagellum, there is need of approaches that enable proteomic analysis of individual subdomains. Our work establishes that APEX2 proximity labeling can, indeed, be implemented in the biochemical environment of T. brucei, and has allowed identification of proximity proteomes for different subdomains. This capacity opens the possibility to study the composition and function of other compartments. We further expect that this approach may be extended to other eukaryotic pathogens, and will enhance the utility of T. brucei as a model organism to study ciliopathies, heritable human diseases in which cilia function is impaired.

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