Proteome analysis of breast cancer cells (8701-BC) cultured from primary ductal infiltrating carcinoma: relation to correspondent breast tissues

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Immunological and charge properties of GFAP in lower vertebrates

1. An antiserum specific for bovine GFAP was employed in a comparative study of this protein in several species of bony fish and in an anuran species. 2. The immunological properties of this protein are conserved in a remarkable way in all the species examined. 3. Analysis of trout and bovine GFAP by two-dimensional gel electrophoresis indicated that the charge properties of this protein have remained quite constant from fish to mammals

Proteome analysis of Escherichia coli W3110 expressing an heterologous sigma factor.

The recombinant plasmid pASK18 carries a Streptomyces DNA fragment which includes an open reading frame, designated psfS (putative sigma factor, Streptomyces), as its putative product showed a high degree of similarity with RNA polymerase sigma factors. Previous results showed that PsfS causes transcription initiation within the bgl operon promoter-silencer region in Escherichia coli K12. In this study a proteomic approach has been applied in order to perform a comparative analysis of E. coli K12 W3110 wild-type, W3110 (pASK18) and a W3110 Bgl+ spontaneous mutant. Either by qualitative or quantitative analysis, no significant difference was observed between the proteomes of W3110 and its Bgl+ derivative, while W3110 (pASK18) showed an altered profile by both analyses. Fourteen out of the 37 protein spots showing a different expression level in E. coli W3110 harboring pASK18 were identified by peptide mass fingerprinting. Among the proteins identified, thiol peroxidase (Tpx) was the only one up-regulated. The possible involvement of bgl and tpx in the survival of the pathogen E. coli during infection is discussed

Identification of immunoreactive proteins of Chlamydia trachomatis by Western blot analysis of a two-dimensional electrophoresis map with patient sera.

Western blots of two-dimensional electrophoretic maps of proteins from Chlamydia trachomatis were probed with sera from 17 seropositive patients with genital inflammatory disease. Immunoblot patterns (comprising 28 to 2 spots, average 14.8) were different for each patient; however, antibodies against a spot-cluster due to the chlamydia-specific antigen outer membrane protein-2 (OMP2) were observed in all sera. The next most frequent group of antibodies (15/17; 88%) recognized the hsp60 GroEL-like protein, described as immunopathogenic in chlamydial infections. Reactivity to the major surface-exposed and variable antigen major outer membrane protein (MOMP) was observed at a relatively lower frequency (13/17; 76%). The hsp70 DnaK-like protein was also frequently recognized (11/17; 64.7%) in this patient group. Besides the above confirmatory findings, the study detected several new immunoreactive proteins, with frequencies ranging from 11/17 to 1/17. Some were characterized also by N-terminal amino acid sequencing and homology searches. Amongst these were a novel outer membrane protein (OmpB) and, interestingly, five conserved bacterial proteins: four (23%) sera reacted with the RNA polymerase alpha-subunit, five (29%) recognized the ribosomal protein S1, eight (47%) the protein elongation factor EF-Tu, seven (41%) a putative stress-induced protease of the HtrA family, and seven sera (41%) the ribosomal protein L7/L12. Homologs of the last two proteins were shown to confer protective immunity in other bacterial infections. The data show that immunological sensitization processes commonly thought to play a role in chlamydial pathogenicity may be sustained not only by the hsp60 GroEl-like protein, but also by other conserved bacterial antigens, some of which may be also considered as potential vaccine candidates

Hypoxic response of synaptosomal proteins in term guinea pig fetuses

Early events in the hypoxia-induced response trigger tyrosine phosphorylation cascades involving a large number of enzymes and substrates. The resolving power of advanced two-dimensional gel electrophoresis, followed by immunoblotting with specific antibodies to phosphotyrosine, has been used to analyze hypoxia-induced modifications in guinea pig brain synaptosomes. These procedures, in conjunction with computer-aided image analysis, are useful in the differential display of gene products, providing comparison at the level of posttranslationally modified products. Studies were performed in cerebral cortical synaptosomes from three normoxic and three hypoxic newborn guinea pigs. To filter off background noise consisting of nonreproducible migrating protein spots, only reproducible features of electrophoretic patterns were considered. Immunoreactivity patterns obtained with anti-phosphotyrosine antibodies proved to be different in normoxic and hypoxic synaptosomes: of a total of 130 immunoreactive spots, 49 were tyrosine-phosphorylated in hypoxic synaptosomes only and 20 in the normoxic ones only. Our data suggest that hypoxia extensively remodels the signaling pathway by switching off tyrosine phosphorylation of some cellular components (i.e., alpha-internexin) and switching on tyrosine phosphorylation of some other proteins (i.e., heat shock cognate 70, aconitase, 2',3'-cyclic nucleotide 3'-phosphodiesterase, and pyruvate kinase)

Extensive temporally regulated reorganization of the lipid raft proteome following T-cell antigen receptor triggering.

Signalling by immunoreceptors is orchestrated at specific plasma membrane microdomains, referred to as lipid rafts. Here we present a proteomics approach to the temporal analysis of protein association with lipid rafts following T-cell antigen receptor (TCR) triggering. We show that TCR engagement promotes the temporally regulated recruitment of proteins participating in the TCR signalling cascade to lipid rafts. Furthermore, TCR triggering results in profound modifications in the composition of lipid rafts involving a number of proteins associated either directly or indirectly with both plasma and intracellular membranes. Raft-associated proteins can be clustered according to their temporal profile of raft association. The data identify lipid rafts as highly dynamic structures and reveal a dramatic impact of surface TCR triggering not only on components of the TCR signalling machinery but also on proteins implicated in a number of diverse cellular processes