Search results for "heat shock"
showing 10 items of 303 documents
The Streptomyces coelicolor dnaK operon contains a second promoter driving the expression of the negative regulator hspR at physiological temperature
2006
HspR (heat shock protein regulator) acts as a negative regulator of different genes in many bacteria. In Streptomyces coelicolor hspR gene is part and the transcriptional repressor of the dnaK operon which encodes the DnaK, GrpE, DnaJ chaperone machines and HspR itself. Our experiments led us to the discovery of a second promoter, internal to dnaK operon, located upstream hspR gene. Transcription from this promoter was detected at 30 degrees C indicating that hspR could play a key physiological role.
Expression of a mutant HSP110 sensitizes colorectal cancer cells to chemotherapy and improves disease prognosis
2011
Heat shock proteins (HSPs) are necessary for cancer cell survival. We identified a mutant of HSP110 (HSP110ΔE9) in colorectal cancer showing microsatellite instability (MSI CRC), generated from an aberrantly spliced mRNA and lacking the HSP110 substrate-binding domain. This mutant was expressed at variable levels in almost all MSI CRC cell lines and primary tumors tested. HSP110ΔE9 impaired both the normal cellular localization of HSP110 and its interaction with other HSPs, thus abrogating the chaperone activity and antiapoptotic function of HSP110 in a dominant-negative manner. HSP110ΔE9 overexpression caused the sensitization of cells to anticancer agents such as oxaliplatin and 5-fluorou…
Changes in immunohistochemical levels and subcellular localization after therapy and correlation and colocalization with CD68 suggest a pathogenetic …
2011
In an earlier work, the role of heat shock protein (Hsp60) in the pathogenesis of ulcerative colitis (UC) was suggested by its significant increase in the pathological mucosa parallel with an increase in inflammatory cells. More data in this direction are reported in this work. We analyzed by immunohistochemistry biopsies of colon tissue from 2 groups of patients with UC and treated with either 5-aminosalicylic acid (5-ASA) alone or in combination with a probiotic. We looked for inflammatory markers and Hsp60. Both the treatments were effective in reducing symptoms but the group treated with both 5-ASA and probiotics showed better clinical results. Amelioration of symptoms was associated wi…
The expression of heat shock proteins 27 and 105 in squamous cell carcinoma of the tongue and relationship with clinicopathological index
2010
Introduction: In oral cavity, the tongue is the most common site prone to development of squamous cell carcinoma (SCC). Considering malignant transformation as a cellular stress, the expression of heat shock proteins (HSPs) may be affected in this process. In this study we assessed the expression of HSP105 and HSP27 as two of the most interested stress proteins and investigated their relationship with grade and stage of the tongue SCC. Material and Methods: Fifty-six specimens including 31 early and 25 advanced tongue SCC were gathered. All specimens were graded histologically from I to III. Sixteen sections of normal oral mucosa were used as control group. The cellularity and intensity of …
Heat shock proteins in three relatedDrosophila species belonging to theobscura group
1993
The effect of heat shock on protein synthesis in three related Drosophila species belonging to the obscura group was analyzed on SDS-acrylamide gels. Four major heat shock proteins (hsps) were found in these species, in which synthesis reaches a maximum at 34 degrees C. Although the higher molecular weight proteins are conserved, differences in size were found for the small hsps in these species. By means of in situ hybridization using D. melanogaster probes for the small hsp genes, it was inferred that the small hsp genes of the obscura group species are clustered at the 27A locus in all three species.
Thermostability of Two Cyanobacterial GrpE Thermosensors
2011
GrpE proteins act as co-chaperones for DnaK heat-shock proteins. The dimeric protein unfolds under heat stress conditions, which results in impaired interaction with a DnaK protein. Since interaction of GrpE with DnaK is crucial for the DnaK chaperone activity, GrpE proteins act as a thermosensor in bacteria. Here we have analyzed the thermostability and function of two GrpE homologs of the mesophilic cyanobacterium Synechocystis sp. PCC 6803 and of the thermophilic cyanobacterium Thermosynechococcus elongatus BP1. While in Synechocystis an N-terminal helix pair of the GrpE dimer appears to be the thermosensing domain and mainly mediates GrpE dimerization, the C-terminal four-helix bundle i…
Manipulation of HSP70-SOD1 Expression Modulates SH-SY5Y Differentiation and Susceptibility to Oxidative Stress-Dependent Cell Damage: Involvement in …
2023
The differentiation of neural progenitors is a complex process that integrates different signals to drive transcriptional changes, which mediate metabolic, electrophysiological, and morphological cellular specializations. Understanding these adjustments is essential within the framework of stem cell and cancer research and therapy. Human neuroblastoma SH-SY5Y cells, widely used in neurobiology research, can be differentiated into neuronal-like cells through serum deprivation and retinoic acid (RA) supplementation. In our study, we observed that the differentiation process triggers the expression of Heat Shock Protein 70 (HSP70). Notably, inhibition of HSP70 expression by KNK437 causes a dra…
Combinatory effects of temperature stress and nonionic organic pollutants on stress protein (hsp70) gene expression in the freshwater spongeEphydatia…
1995
This is the first documentation of a heat shock protein (hsp) response in sponges. Subjecting the freshwater sponge Ephydatia fluviatilis to temperature stress (18 to 33 C; 2 h) resulted in an increased expression (>10 times) of the M{sub r}70,000 (hsp70). The induction of hsp70 could be demonstrated on the level of gene expression and by quantification of the hsp70 protein. Temperature stress also resulted in a 25% reduction of sponge cell proliferation. A mixture of nonionic organic compound was extracted from water from the polluted Schwarzbach River (S. Hesse, Germany) by adsorption onto XAD-7 resin. Concentrations of this Schwarzbach River water extract at two and four items ambient le…
Heat shock proteins: essential proteins for apoptosis regulation
2008
Abstract Many different external and intrinsic apoptotic stimuli induce the accumulation in the cells of a set of proteins known as stress or heat shock proteins (HSPs). HSPs are conserved proteins present in both prokaryotes and eukaryotes. These proteins play an essential role as molecular chaperones by assisting the correct folding of nascent and stress-accumulated misfolded proteins, and by preventing their aggregation. HSPs have a protective function, that is they allow the cells to survive to otherwise lethal conditions. Various mechanisms have been proposed to account for the cytoprotective functions of HSPs. Several of these proteins have demonstrated to directly interact with compo…
Short-term exposure to cadmium affects the expression of stress response and apoptosis-related genes in immortalized epithelial cells from the human …
2009
Abstract It is known that cadmium (Cd) evokes cell responses that not only involve protective reactions against toxicity but also induces cell death. Increasing interest has been recently focused on the elucidation of the cellular and molecular aspects of Cd-dependent regulation of gene expression in different model systems. Here, we examined the effects of short-term (24 h) exposure of immortalized non-tumoral HB2 cells from human breast epithelium to CdCl2 at 50 μM concentration, corresponding to the IC50 for this time of incubation. The possible occurrence of apoptosis-related events was evaluated via analysis of the physical state of the DNA and of the membrane localization of phosphaty…