Search results for "chaperon"
showing 10 items of 358 documents
Three-dimensional structure of the anaphase-promoting complex.
2001
The anaphase-promoting complex (APC) is a cell cycle-regulated ubiquitin-protein ligase, composed of at least 11 subunits, that controls progression through mitosis and G1. Using cryo-electron microscopy and angular reconstitution, we have obtained a three-dimensional model of the human APC at a resolution of 24 A. The APC has a complex asymmetric structure 140 A x 140 A x 135 A in size, in which an outer protein wall surrounds a large inner cavity. We discuss the possibility that this cavity represents a reaction chamber in which ubiquitination reactions take place, analogous to the inner cavities formed by other protein machines such as the 26S proteasome and chaperone complexes. This cag…
Heat shock protein 27 is involved in SUMO-2/3 modification of heat shock factor 1 and thereby modulates the transcription factor activity
2009
Heat shock protein 27 (HSP27) accumulates in stressed cells and helps them to survive adverse conditions. We have already shown that HSP27 has a function in the ubiquitination process that is modulated by its oligomerization/phosphorylation status. Here, we show that HSP27 is also involved in protein sumoylation, a ubiquitination-related process. HSP27 increases the number of cell proteins modified by small ubiquitin-like modifier (SUMO)-2/3 but this effect shows some selectivity as it neither affects all proteins nor concerns SUMO-1. Moreover, no such alteration in SUMO-2/3 conjugation is achievable by another HSP, such as HSP70. Heat shock factor 1 (HSF1), a transcription factor responsib…
Proteomic identification of the heterogeneous nuclear ribonucleoprotein K as irradiation responsive protein related to migration
2014
Abstract Irradiation resistance is a major obstacle of head and neck squamous cell carcinoma (HNSCC) therapy, limiting treatment success and patient survival. The aim of our experiments was to identify irradiation-regulated proteins as potential drug targets. Two established HNSCC cell lines (HNSCCUM-01T and HNSCCUM-02T) were treated with a single 8 Gy (Gray) fraction of irradiation. Changes in cellular protein expression were studied after 24 h by means of 2D-electrophoresis and MALDI–TOF-mass spectrometry. Ninety-four differentially expressed proteins were identified. The expression levels of four proteins were regulated similarly in both cell lines after irradiation treatment, i.e., GRP7…
The Chaperonopathies: Classification, Mechanisms, Structural Features
2013
The classification of chaperonopathies is presented in this chapter. Like many other diseases, chaperonopathies can be genetic or acquired, primary or secondary, structural and/or functional, and qualitative and/or quantitative. In addition, considering pathogenic mechanism, chaperonopathies can be by defect, excess, or mistake. In the latter, a chaperone is normal but favors disease, a situation that occurs, for instance, in various types of cancers. Structural chaperonopathies are characterized by a change in the molecule of a chaperone due to mutation (genetic chaperonopathy) or due to aberrant post-translational modification (acquired chaperonopathy). In both cases, the impact of the st…
Induction of stress proteins in human endothelial cells by heavy metal ions and heat shock.
1999
In the present study, we compared the induction of heat shock proteins (HSPs) by heat and heavy metal ions in three different endothelial cell types, namely, human umbilical vein endothelial cells, human pulmonary microvascular endothelial cells, and the cell line EA.hy 926. Our results show that especially Zn2+and Cd2+are inducers of 70-kDa (HSP70), 60-kDa (HSP60), 32-kDa (HSP32), and 27-kDa (HSP27) HSPs. The strength of inducibility is specific for each HSP. Ni2+and Co2+only show an inducible effect at very high concentrations, that is, in the clearly cytotoxic range. Furthermore, we investigated the time course of HSP expression and the involvement of heat shock factor-1. Our study demon…
Molecular chaperones and mirnas in epilepsy: Pathogenic implications and therapeutic prospects
2021
Epilepsy is a pathologic condition with high prevalence and devastating consequences for the patient and its entourage. Means for accurate diagnosis of type, patient monitoring for predicting seizures and follow up, and efficacious treatment are desperately needed. To improve this adverse outcome, miRNAs and the chaperone system (CS) are promising targets to understand pathogenic mechanisms and for developing theranostics applications. miRNAs implicated in conditions known or suspected to favor seizures such as neuroinflammation, to promote epileptic tolerance and neuronal survival, to regulate seizures, and others showing variations in expression levels related to seizures are promising ca…
Molecular Chaperones and Thyroid Cancer
2021
Thyroid cancers are the most common of the endocrine system malignancies and progress must be made in the areas of differential diagnosis and treatment to improve patient management. Advances in the understanding of carcinogenic mechanisms have occurred in various fronts, including studies of the chaperone system (CS). Components of the CS are found to be quantitatively increased or decreased, and some correlations have been established between the quantitative changes and tumor type, prognosis, and response to treatment. These correlations provide the basis for identifying distinctive patterns useful in differential diagnosis and for planning experiments aiming at elucidating the role of t…
A genetic approach reveals different modes of action of prefoldins
2021
17 p.-7 fig.
DICER and ZRF1 contribute to chromatin decondensation during nucleotide excision repair
2016
Abstract Repair of damaged DNA relies on the recruitment of DNA repair factors in a well orchestrated manner. As a prerequisite, the chromatin needs to be decondensed by chromatin remodelers to allow for binding of repair factors and for DNA repair to occur. Recent studies have implicated members of the SWI/SNF and INO80 families as well as PARP1 in nucleotide excision repair (NER). In this study, we report that the endonuclease DICER is implicated in chromatin decondensation during NER. In response to UV irradiation, DICER is recruited to chromatin in a ZRF1-mediated manner. The H2A–ubiquitin binding protein ZRF1 and DICER together impact on the chromatin conformation via PARP1. Moreover, …
Heat Shock Protein-60 and Risk for Cardiovascular Disease
2011
Cardiovascular disease (CVD) is a leading cause of morbidity and mortality worldwide. There is growing evidence that molecularchaperones, many of which are heat shock proteins HSPs, are involved in CVD pathogenesis. In this review we focus on HSP60,the human mitochondrial chaperone that also displays extramitochondrial and extracellular functions. HSP60 is typically cytoprotectivebut a number of stress conditions determine its conversion to a potentially toxic molecule for cells and tissues. We present illustrative examplesof specific subtypes of CVD where HSP60 is implicated in the initiation and/or progression of disease. The data not only indicatea pathogenic role for HSP60 but also its …