Autophagy is a physiological process which delivers the mutant cytoplasmic proteins and dysfunctional subcellular organs into lysosomes for degradation to generate fuel in the deficiency conditions. It is mainly classified into macroautophagy, microautophagy and chaperon-mediated autophagy (CMA), as well as the selective autophagy such as mitophagy and aggrephagy. This review mainly introduces the key molecular markers of macroautophagy, CMA and mitophagy.
Autophagy ; Humans ; Lysosomes ; Mitochondrial Degradation ; Molecular Chaperones

Huntington's disease (HD) is a late-onset and progressive neurodegenerative disorder that is caused by aggregation of mutant huntingtin protein which contains expanded-polyglutamine. The molecular chaperones modulate the aggregation in early stage and known for the most potent protector of neurodegeneration in animal models of HD. Over the past decades, a number of studies have demonstrated molecular chaperones alleviate the pathogenic symptoms by polyQ-mediated toxicity. Moreover, chaperone-inducible drugs and anti-aggregation drugs have beneficial effects on symptoms of disease. Here, we focus on the function of molecular chaperone in animal models of HD, and review the recent therapeutic approaches to modulate expression and turn-over of molecular chaperone and to develop anti-aggregation drugs.
Huntington Disease* ; Models, Animal ; Molecular Chaperones ; Neurodegenerative Diseases

Humans ; Leukemia, Myeloid, Acute ; Molecular Chaperones ; Tumor Suppressor Proteins

Heat shock proteins are a class of molecular chaperones that can be found in nearly all organisms from Bacteria, Archaea and Eukarya domains. Heat shock proteins experience increased transcription during periods of heat induced osmotic stress and are involved in protein disaggregation and refolding as part of a cell's danger signaling cascade. Heat shock protein, Hsp20 is a small molecular chaperone that is approximately 20kDa in weight and is hypothesized to prevent aggregation and denaturation. Hsp20 can be found in several strains of Proteobacteria, which comprises the largest phyla of the Bacteria domain and also contains several medically significant bacterial strains. Genomic analyses were performed to determine a common evolutionary pattern among Hsp20 sequences in Proteobacteria. It was found that Hsp20 shared a common ancestor within and among the five subclasses of Proteobacteria.This is readily apparent from the amount of sequence similarities within and between Hsp20 protein sequences as well as phylogenetic analysis of sequences from proteobacterial and non-proteobacterial species.
Actinobacteria ; Archaea ; Bacteria ; Computational Biology ; Eukaryota ; Heat-Shock Proteins ; Hot Temperature ; Molecular Chaperones ; Proteins ; Proteobacteria ; Shock

Cancer cells typically display increased rates of aerobic glycolysis that are correlated with tumor aggressiveness and a poor prognosis. Targeting the glycolytic pathway has emerged as an attractive therapeutic route mainly because it should spare normal cells. Here, we evaluate the effects of combining the inhibition of glycolysis with application of the polyphenolic compound resveratrol (RSV) in neuroblastoma (NB) cancer cell lines. Inhibiting glycolysis with 2-deoxy-D-glucose (2-DG) significantly reduced NB cell viability and was associated with increased endoplasmic reticulum (ER) stress and Akt activity. Administration of 2-DG increased the expression of the ER molecular chaperones GRP78 and GRP94, the prodeath protein C/EBP homology protein (CHOP) and the phosphorylation of Akt at S473, T450 and T308. Combined treatment with both RSV and 2-DG reduced GRP78, GRP94 and Akt phosphorylation but increased CHOP and NB cell death when compared with the administration of 2-DG alone. The selective inhibition of Akt activity also decreased 2-DG-induced GRP78 and GRP94 expression and increased CHOP expression, suggesting that Akt can modulate ER stress. Protein phosphatase 1α (PP1α) was activated by RSV, as indicated by a reduction in PP1α phosphorylation at T320. Pretreatment of cells with tautomycin, a selective PP1α inhibitor, prevented the RSV-mediated decrease in Akt phosphorylation, suggesting that RSV enhances 2-DG-induced cell death by activating PP1 and downregulating Akt. The RSV-mediated inhibition of Akt in the presence of 2-DG was not prevented by the selective inhibition of SIRT1, a known target of RSV, indicating that the effects of RSV on this pathway are independent of SIRT1. We propose that RSV inhibits Akt activity by increasing PP1α activity, thereby potentiating 2-DG-induced ER stress and NB cell death.
Cell Death ; Cell Line ; Cell Survival ; Deoxyglucose ; Endoplasmic Reticulum ; Glycolysis ; Molecular Chaperones ; Neuroblastoma* ; Phosphorylation ; Prognosis

Proteins in DNAJ/K families are ubiquitous, from prokaryotes to eukaryotes, and function as molecular chaperones. For systematic phylogenomics of the DNAJ/K families, we developed the Eukaryotic DNAJ/K Database (EDD). A total of 12,908 DNAJs and 4,886 DNAKs were identified from 339 eukaryotic genomes in the EDD. Kingdom-wide comparison of DNAJ/K families provides new insights on the evolutionary relationship within these families. Empowered by 'class', 'cluster', and 'taxonomy' browsers and the 'favorite' function, the EDD provides a versatile platform for comparative genomic analyses of DNAJ/K families.
Eukaryota ; Genome ; HSP40 Heat-Shock Proteins ; HSP70 Heat-Shock Proteins ; Humans ; Molecular Chaperones ; Proteins

OBJECTIVETo identify the specific protein interactions involved in Bat3-mediated apoptosis.

METHODSTandem affinity purification (TAP) was utilized to investigate Bat3-protein interactions, during which full-length human Bat3 fused with Strep2 and FLAG tag as a bait was used to screen the specific protein-protein interactions. The isolated proteins were identified with mass spectrometry.

RESULTSTAP studies showed that Ubl4A was identified as a Bat3-binding partner. Further investigation using co-immunoprecipitation confirmed that Bat3 was associated with Ubl4A.

CONCLUSIONTAP was successfully established and is suitable for isolating the binding partners of Bat3.

OBJECTIVETo investigate the expression and correlation of mast cell, Clusterin/apoJ and transforming growth factor-beta (TGF-beta) in the different stages of human dermal hemangioma.

METHODSImmunohistochemical stain technique (SABC) and toluidine blue (TB) stain technique were respectively used to detect the expression level of Clusterin/apoJ and TGF-beta and the number of mast cells in the different stages of human dermal hemangioma.

RESULTSThere was remarkable statistical difference between the advanced stage of proliferative hemangioma and the other stages of proliferative hemangioma in the number of mast cell(P<0.01). There was also remarkable statistical difference between the early stage of involutional hemangioma and the other stages of involutional hemangioma in the number of mast cell (P<0.01). The expression of Clusterin/apoJ and TGF-beta in the advanced stage of proliferative hemangioma was significantly higher than the other stages in proliferative hemangioma (P<0.01). The expression of Clusterin/apoJ and TGF-beta in the early stage of involutional hemangioma was significantly higher than the other stages in involutional hemangioma (P<0.01). There was a significantly positive correlation between Clusterin/apoJ and TGF-beta in the different stages of human dermal hemangioma (P<0.01). The expression level of Clusterin/apoJ and TGF-beta was positively correlated with the number of mast cell in the different stages of human dermal hemangioma (P<0.01).

CONCLUSIONMast cell may play a promotive role of apoptosis during the spontaneous regulate the expression of Clusterin/apoJ and promote the spontaneous involution of human dermal hemangioma.

The formation of most proteins consists of two steps: the synthesis of precursor proteins and the synthesis of functional proteins. In these processes, propeptides play important roles in assisting protein folding or inhibiting its activity. As an important polypeptide chain coded by a gene sequence in lipase gene, propeptide usually functions as an intramolecular chaperone, assisting enzyme molecule folding. Meanwhile, some specific sites on propeptide such as glycosylated sites, have important effect on the activity, stability in extreme environment, methanol resistance and the substrate specificity of the lipase. Studying the mechanism of propeptide-mediated protein folding, as well as the influence of propeptide on lipases, will allow to regulate lipase by alternating the propeptide folding behavior and in turn pave new ways for protein engineering research.
Lipase/metabolism* ; Molecular Chaperones/metabolism* ; Protein Folding ; Protein Precursors ; Substrate Specificity

Diphtheria toxin is an ADP-ribosyltransferase toxic to human cells. Mutation of the active site in its catalytic domain eliminates the toxicity, but retains its immunogenicity. A non-toxic mutant of diphtheria toxin known as CRM197 protein has become an ideal carrier protein for conjugate vaccines. CRM197 can further improve its immunogenicity by cross-linking with other antigens, so it has good potential to find broad applications. Unfortunately, inclusion bodies are easily formed during the expression of recombinant CRM197 protein in Escherichia coli, which greatly reduces its yield. In order to address this problem, pG-KJE8 vector carrying molecular chaperones and plasmid pET28a-CRM197, were co-expressed in Escherichia coli. The results showed that the recombinant CRM197 protein was successfully expressed and appeared largely in inclusion bodies. The molecular chaperones DnaK, DnaJ, GrpE, GroES and GroEL5 expressed can facilitate correct and rapid folding of CRM197. Furthermore, it can also improve the recovery rate of soluble CRM197 protein. The soluble expression of CRM197 was maximized upon addition of 1.0 mmol/L IPTG, 0.5 mg L-arabinose, 5.0 ng/mL tetracycline and induction at 20oC for 16 h. The soluble CRM197 protein shows good immunoreactivity, demonstrating the molecular chaperones expressed from pG-KJE8 facilitated the soluble expression of CRM197 protein in E. coli.
Bacterial Proteins ; Diphtheria Toxin/genetics* ; Escherichia coli/genetics* ; Humans ; Molecular Chaperones/genetics* ; Recombinant Proteins/genetics*