Search results for "Chaperone"

Membrane-anchored heat-shock protein 70 (Hsp70) in cancer.

2020

International audience; Hsp70 is a highly conserved and inducible heat shock protein that belongs to the HSP70 family of molecular chaperones and plays a central role in protein homeostasis. The main function of Hsp70 is to protect cells from physiological, pathological and environmental insults, as it assists an ATP-dependent manner the process of protein folding. Since Hsp70 provides critical cell survival functions, cancer cells are assumed to rely on this chaperone. Strong evidence suggests that Hsp70 is upregulated in different type of cancers and is involved in tumor growth, invasion, migration and resistance to anti-cancer therapy. Interestingly, this Hsp70 upregulation induces Hsp70…

Hypoxia-Inducible Factor-1α Activity as a Switch for Glioblastoma Responsiveness to Temozolomide

2018

Rationale: The activity of the transcription factor, hypoxia-inducible factor (HIF)-1?, is a common driver of a number of the pathways involved in the aggressiveness of glioblastomas (GBMs), and it has been suggested that the reduction in this activity observed, soon after the administration of temozolomide (TMZ), can be a biomarker of an early response in GBM models. As HIF-1? is a tightly regulated protein, studying the processes involved in its downregulation could shed new light on the mechanisms underlying GBM sensitivity or resistance to TMZ. Methods: The effect of HIF-1? silencing on cell responsiveness to TMZ was assessed in four genetically different human GBM cell lines by evaluat…

Alzheimer's Disease and Molecular Chaperones: Current Knowledge and the Future of Chaperonotherapy

2016

Background: Alzheimer’s disease (AD) is a dementia, a neurodegenerative condition, and a protein-misfolding disease or proteinopathy, characterized by protein deposits, extracellular plaques and intracellular neurofibrillary tangles, which contain the AD’s typical pathological proteins, abnormal [1]-amyloid and hyperphosphorylated tau, respectively, and are located predominantly in the cortex of the frontal, parietal, and temporal brain lobes. What is the role of molecular chaperones in AD? Data indicate that molecular chaperones, also known as Hsp, are involved in AD, probably displaying protective roles and/or acting as pathogenic factors as it occurs in chaperonopathies in which case AD …

The Binding Mechanism of Epolactaene to Hsp60 Unveiled by in Silico Modelling

2016

Molecular Dynamics (MD) simulations and DFT/MM calculations were performed in order to rationalize available experimental results and to provide structural details on the binding mechanism of Epolactaene (EPO) to the 60 KDa Heat Shock Protein (Hsp60). The available crystal structure of Hsp60 represents the last step of the chaperone folding cycle, while the Hsp60-EPO complex was obtained by using a homology model of Hsp60, in order to simulate a state related to the beginning of the folding cycle (Rs1). The results of MD simulations point out that EPO shows the highest binding affinity for the empty ATP binding site. The presence of ATP opens a channel that allows the entrance of both EPO d…

2020

Hsp70 proteins and their Hsp40 co-chaperones are essential components of cellular chaperone networks in both prokaryotes and eukaryotes. Here, we performed a genetic analysis to define the protein domains required for the key functions of the major Hsp40/DnaJ protein Sll0897 of the cyanobacterium Synechocystis sp. PCC6803. The expression of the N-terminally located J- and G/F-domains is essential and sufficient for the proteins' fundamental in vivo functions, whereas the presence of the full-length protein, containing the C-terminal substrate-binding domains, is crucial under stress conditions.

Membrane chaperoning by members of the PspA/IM30 protein family

2017

ABSTRACTPspA, IM30 (Vipp1) and LiaH, which all belong to the PspA/IM30 protein family, form high molecular weight oligomeric structures. For all proteins membrane binding and protection of the membrane structure and integrity has been shown or postulated. Here we discuss the possible membrane chaperoning activity of PspA, IM30 and LiaH and propose that larger oligomeric structures bind to stressed membrane regions, followed by oligomer disassembly and membrane stabilization by protein monomers or smaller/different oligomeric scaffolds.

Hsp40 Is Involved in Cilia Regeneration in Sea Urchin Embryos

2003

In a previous paper we demonstrated that, in Paracentrotus lividus embryos, deciliation represents a specific kind of stress that induces an increase in the levels of an acidic protein of about 40 kD (p40). Here we report that deciliation also induces an increase in Hsp40 chaperone levels and enhancement of its ectodermal localization. We suggest that Hsp40 might play a chaperoning role in cilia regeneration.

Genetics and Gene Therapy of Anderson-Fabry Disease.

2018

Fabry's disease is a genetic disorder of X-linked inheritance caused by mutations in the alpha galactosidase A gene resulting in deficiency of this lysosomal enzyme. The progressive accumulation of glycosphingolipids, caused by the inadequate enzymatic activity, is responsible of organ dysfunction and thus of clinical manifestations. In the presence of a high clinical suspicion, a careful physical examination and specific laboratory tests are required, finally diagnosis of Fabry's disease is confirmed by the demonstration of absence or reduced alpha-galactosidase A enzyme activity in hemizygous men and gene typing in heterozygous females; in fact the performance of enzymatic activity assay …

Treatment strategies for lysosomal storage disorders.

2017

Over the past several years the number of treatments available for patients with lysosomal storage disorders has rapidly increased. Haematopoietic stem cell transplantation, enzyme replacement therapy, substrate reduction, and chaperone therapies are currently available, and gene therapies and other treatments are rapidly advancing. Despite remarkable advances, the efficacy of most of these therapies is limited, particularly because the treatments are usually initiated when organ damage has already occurred. To circumvent this limitation, screening in newborn infants for lysosomal storage disorders has been introduced in many countries. However, this screening is complicated by the broad cl…

Zebrafish as a Model for the Study of Chaperonopathies

2016

There is considerable information on the clinical manifestations and mode of inheritance for many genetic chaperonopathies but little is known on the molecular mechanisms underlying the cell and tissue abnormalities that characterize them. This scarcity of knowledge is mostly due to the lack of appropriate animal models that mimic closely the human molecular, cellular, and histological characteristics. In this article we introduce zebrafish as a suitable model to study molecular and cellular mechanisms pertaining to human chaperonopathies. Genetic chaperonopathies manifest themselves from very early in life so it is necessary to examine the impact of mutant chaperone genes during developmen…