Search results for "Chaperonins"

Doxorubicin anti-tumor mechanisms include Hsp60 post-translational modifications leading to the Hsp60/p53 complex dissociation and instauration of re…

2017

Hsp60 is a pro-carcinogenic chaperonin in certain tumor types by interfering with apoptosis and with tumor cell death. In these tumors, it is not known whether or not doxorubicin anti-tumor effects include a blockage of the pro-carcinogenic action of this protein. We used the human lung mucoepidermoid cell line NCI-H292 and different doses of doxorubicin to measure cell viability, cell cycle progression, cell senescence indicators, Hsp60 levels and its post-translational modifications as well as the release of the chaperonin into the extracellular environment. Cell viability was reduced in relation to doxorubicin dose and this was paralleled by the appearance of cell senescence markers. Con…

Chaperonin of Group I: Oligomeric spectrum and biochemical and biological implications

2018

Chaperonins play various physiological roles and can also be pathogenic. Elucidation of their structure, e.g., oligomeric status and post-translational modifications (PTM), is necessary to understand their functions and mechanisms of action in health and disease. Group I chaperonins form tetradecamers with two stacked heptameric rings. The tetradecamer is considered the typical functional complex for folding of client polypeptides. However, other forms such as the monomer and oligomers with smaller number of subunits than the classical tetradecamer, also occur in cells. The properties and functions of the monomer and oligomers, and their roles in chaperonin-associated diseases are still inc…

Progressive Characterization of Visual Phenotype in Bardet-Biedl Syndrome Mutant Mice

2019

Purpose Bardet-Biedl syndrome (BBS) is an archetypical ciliopathy caused by defective ciliary trafficking and consequent function. Insights gained from BBS mouse models are applicable to other syndromic and nonsyndromic retinal diseases. This progressive characterization of the visual phenotype in three BBS mouse models sets a baseline for testing therapeutic interventions. Methods Longitudinal acquisition of electroretinograms, optical coherence tomography scans, and visual acuity using the optomotor reflex in Bbs6/Mkks, Bbs8/Ttc8, and Bbs5 knockout mice. Gene and protein expression analysis in vivo and in vitro. Results Complete loss of BBS5, BBS6, or BBS8 leads to different rates of reti…

Hsp60 Friend and Foe of the Nervous System

2019

Hsp60 belongs to the subgroup of molecular chaperones named chaperonins and, typically, resides and functions in the mitochondria but it is also present in extramitochondrial sites. It chaperones client peptides as they fold to achieve the native conformation and also displays anti-stress roles by helping stress-damaged proteins regain a functional shape. Thus, Hsp60 is central to the integrity and functionality of mitochondria and energy production. All cells in the nervous system depend on Hsp60 so when the chaperonin malfunctions the consequences on nervous tissues are usually devastating, causing diverse diseases. These are the Hsp60 chaperonopathies, which can be genetic or acquired wi…

Human Hsp10 and Early Pregnancy Factor (EPF) and their relationship and involvement in cancer and immunity: current knowledge and perspectives.

2009

This article is about Hsp10 and its intracellular and extracellular forms focusing on the relationship of the latter with Early Pregnancy Factor and on their roles in cancer and immunity. Cellular physiology and survival are finely regulated and depend on the correct functioning of the entire set of proteins. Misfolded or unfolded proteins can cause deleterious effects and even cell death. The chaperonins Hsp10 and Hsp60 act together inside the mitochondria to assist protein folding. Recent studies demonstrated that these proteins have other roles inside and outside the cell, either together or independently of each other. For example, Hsp10 was found increased in the cytosol of different t…

CtsR is the master regulator of stress response gene expression in Oenococcus oeni.

2005

ABSTRACT Although many stress response genes have been characterized in Oenococcus oeni , little is known about the regulation of stress response in this malolactic bacterium. The expression of eubacterial stress genes is controlled both positively and negatively at the transcriptional level. Overall, negative regulation of heat shock genes appears to be more widespread among gram-positive bacteria. We recently identified an ortholog of the ctsR gene in O. oeni . In Bacillus subtilis , CtsR negatively regulates expression of the clp genes, which belong to the class III family of heat shock genes. The ctsR gene of O. oeni is cotranscribed with the downstream clpC gene. Sequence analysis of t…

Human HSP10 variants downregulation after cigarette smoke extract exposure in lung cells

2009

The impact of cigarette-smoke stress (a form of oxidative stress) on human lung fibroblasts and epithelial cells, particularly its effect on Hsp10 expression, has not been characterized despite the fact that a role for mitochondrial chaperonins in the development of lung diseases, ranging from chronic obstructive pulmonary disease to bronchial carcinogenesis, has been suggested (1). We studied the effects of non-lethal doses of cigarette smoke extract (CSE) on the expression of Hsp10 in human lung fibroblasts (HFL-1 line) and epithelial cells (16HBE line). Proteomics was carried out using 2D-IPG, silver stain, western blotting, and mass-spectrometry; mRNA was measured by RT-PCR. Database se…

Distribution of mitochondrial chaperonins in lung cells

2011

Gene expression in mouse spermatogenesis during ontogenesis

2006

In this study, we evaluated the expression of genes probably involved in spermatogenesis in the mouse. We examined cytosolic chaperonin theta subunit (CCTtheta), Ngg1 interacting factor 3 like 1 binding protein 1 (NIF3L1 BP1) and apolipoprotein H (ApoH) expression during mouse onto-geny using RT-PCR. Testicular tissue was obtained from mice 3, 6, 8, 10, 12, 14, 18, 20 and 40 (adult) days after birth. For each mouse, one testis was used for histological examination, whereas RNA was extracted from the controlateral testis for expression analysis. RT-PCR analysis showed that CCTtheta gene expression was low until day 10, but increased drastically afterwards. At this age, spermatocytes started …

Hsp60 expression, new locations, functions and perspectives for cancer diagnosis and therapy.

2008

Hsp60 in eukaryotes is considered typically a mitochondrial chaperone (also called Cpn60) but in the last few years it has become clear that it also occurs in the cytosol, the cell surface, the extracellular space, and in the peripheral blood. Studies with prokaryotic models have shown that Hsp60 plays a role in assisting nascent polypeptides to reach a native conformation, and that it interacts with Hsp10 (which also resides in the mitochondria and is also named Cpn10). In addition to its role in polypeptide folding in association with Hsp10, other functions and interacting molecules have been identified for Hsp60 in the last several years. Some of these newly identified functions are asso…