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

Objective: To investigate the expression characteristic of the Daxx gene in the mouse testis and its role in spermatogenesis. METHODS: Real-time PCR, Western blot and immunofluorescence were used in examining the expression characteristics of DAXX in the testis tissue from wild-type, Sertoli cell-specific androgen receptor knockout (SCARKO) and androgen receptor knockout (ARKO) mice at different postnatal weeks . RESULTS: The Daxx gene was highly expressed in the testis tissue and mainly in the nuclei of the wild-type mice at 4 postnatal weeks. Compared with the wild-type, the ARKO mice showed a markedly decreased expression of DAXX (0.299±0.026), which displayed a polar distribution in the spermatogenic cells (0.853±0.058) and exhibited no significant difference in the SCARKO mice (1.000±0.015). CONCLUSIONS The Daxx gene expression is the highest in the middle-stage development of the mouse testis, significantly decreased in ARKO mice as compared with the wild-type, and its location influenced by specific AR knockout in Sertoli cells. DAXX may be involved in the regulation of spermatogenesis in mice.
Animals ; Carrier Proteins ; genetics ; metabolism ; Cell Nucleus ; genetics ; metabolism ; Gene Expression ; Intracellular Signaling Peptides and Proteins ; genetics ; metabolism ; Male ; Mice ; Mice, Knockout ; Molecular Chaperones ; Nuclear Proteins ; genetics ; metabolism ; Receptors, Androgen ; genetics ; Sertoli Cells ; Spermatogenesis ; genetics ; Testis ; metabolism

To analyze the differentially expressed proteins which interacted with NF-kappaB in the uterine lower segment smooth muscle tissues under different status of labor onset, and to provide a new foundation on the mechanisms for labor onset.
 Methods: NF-κB P65 protein expression in smooth muscle tissues from the term non-labor group, natural term labor group and drug-induced term labor group was analyzed by Western blot. Co-immunoprecipitation and SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis) were performed to detect the proteins interacting with NF-κB p65 in the NF-κB p65 complexes. The components of the complex were identified by LC-ESI-MS/MS (liquid chromatography-tandem electrospray mass spectrometry) and database analysis. The identified differentially expressed proteins were confirmed by Western blot.
 Results: Positive expression of NF-κB was detected in all of the three groups. 10 differentially expressed proteins were identified by LC-ESI-MS/MS in human lower segment myometrium tissues in the term non-labor group and natural term labor group, mean while, 5 differentially expressed proteins were identified in the term non-labor group and the drug-induced labor group. 3 differential expression proteins were detected in all of the 3 groups, including Heat shock 70, Annexin A6 and Desmin, which were verified by Western blot. These proteins were mainly involved in chaperone, signal transduction, cell structure, and energy metabolism process, respectively.
 Conclusion: NF-κB expressed in uterine smooth muscle cells is involved in the process of initiation and regulation of labor onset through a number of proteins relevant to signal transduction, cell structure and energy metabolism.
Blotting, Western ; Electrophoresis, Polyacrylamide Gel ; Energy Metabolism ; genetics ; Female ; Humans ; Immunoprecipitation ; Labor, Obstetric ; genetics ; Molecular Chaperones ; genetics ; Myocytes, Smooth Muscle ; Myometrium ; physiology ; NF-kappa B ; genetics ; physiology ; Pregnancy ; Protein Interaction Mapping ; Proteomics ; Signal Transduction ; genetics ; Tandem Mass Spectrometry ; Transcription Factor RelA

OBJECTIVETo explore the expressions of HO-2 and CO in the corpus cavernosum of castrated rats in order to further study the pathogenesis of erectile dysfunction (ED).

METHODSWe randomly divided 72 male SD rats into four groups: normal control, sham operation, castration, and castration + ZnPP. We detected intracavernous pressure (ICP) and penile erection in the basic condition and after apomorphine (APO) induction, determined the expression of the HO-2 protein in the corpus cavernosum by laser scanning confocal microscopy, and measured the level of CO by spectrophotometry during different periods of penile erection.

RESULTSThe ICP in the basic condition and that after APO induction and the rate of penile erection were decreased significantly in the castration group ([11.68 ± 0.69] mmHg, [54.81 ± 3.86] mmHg, and 33.3%) and the castration + ZnPP group ([11.20 ± 0.71] mmHg, [41.17 ± 5.41] mmHg, and 22.2%) as compared with the normal control ([22.83 ± 2.66] mmHg, [66.92 ± 7.77] mm-Hg, and 100%) and the sham operation group ([23.35 ±2.22] mmHg, [70.43 ?7. 22] mmHg, and 100%) (all P <0. 01). After APO induction, ICP in the castration + ZnPP group was remarkably reduced in comparison with that in the castration group (P < 0.01), and so was the expression of the HO-2 protein before and during penile erection in the castration (445.4 ± 23.7 and 847.4 ± 35.0) and the castration + ZnPP group (390.1 ± 29.7 and 526.0 ± 52.5) compared with the normal control (512.7 ±57.4 and 1145.2 ± 89.8) and the sham operation group (583.7 ± 8.0 and 1016.3 ± 79.8), the expression of the HO-2 protein significantly decreased in the castration group (445.4 ± 23.7 and 847.4 ± 35.0) (P < 0.05 or 0.01), markedly lower in the castration + ZnPP than in the castration group during penile erection (P < 0.01) but with no significant differences among the four groups after it. Before, during and after penile erection, the levels of CO were remarkably decreased in the castration ([20.59 ± 1.01], [32.53 ± 1.26], and [18.71 ± 1.22] x 10(-7) nmol/L) and the castration +ZnPP group ([12.52 ± 1.05], [21.90 ± 1.02], and [16.56 ± 0.55] x 10(-7) nmol/L) as compared with the normal control ([26.76 ± 1.41], [48.25 ± 1.01], and [27.10 ± 1.58 ] x 10(-7) nmol/L) and the sham operation group ([25.41 ± 2.09], [ 47.90 ± 1.22], and [25.67 ± 1.20] x 10(-7) nmol/L) (P < 0.05 or 0.01), significantly lower in the castration + ZnPP than in the castration group during penile erection (P < 0.01).

CONCLUSIONDecreased expressions of HO-2 and CO may correlate with erectile dysfunction in castrated rats.

Animals ; Apomorphine ; pharmacology ; Carbon Monoxide ; metabolism ; Dopamine Agonists ; pharmacology ; Erectile Dysfunction ; etiology ; Humans ; Male ; Molecular Chaperones ; metabolism ; Orchiectomy ; Penile Erection ; drug effects ; Penis ; drug effects ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley

Pichia pastoris is one of the most important systems used in the field of molecular biology for the expression of recombinant proteins. The system has advantages of high expression, high stability, high secretion, easy high-density fermentation and low cost. Many factors affect the expression of recombinant protein, such as gene copy number, codon usage preference, type of promoter, molecular chaperones, glycosylation, signal peptide and fermentation process. In this review, research advances of the above aspects are summarized, which lay a foundation for improving the expression of recombinant proteins in P. pastoris.
Fermentation ; Gene Dosage ; Glycosylation ; Molecular Chaperones ; Pichia ; metabolism ; Promoter Regions, Genetic ; Protein Sorting Signals ; Recombinant Proteins ; biosynthesis

Azacitidine ; pharmacology ; Base Sequence ; Chromosomes, Human, X ; genetics ; DNA Methylation ; drug effects ; DNA Mutational Analysis ; Galactosyltransferases ; metabolism ; Gene Expression Regulation ; drug effects ; Glomerulonephritis, IGA ; etiology ; genetics ; metabolism ; Glycosylation ; Humans ; Immunoglobulin A ; metabolism ; Lipopolysaccharides ; pharmacology ; Lymphocytes ; metabolism ; Molecular Chaperones ; genetics ; metabolism ; Mutation ; Polymorphism, Single Nucleotide

Animals ; Endoplasmic Reticulum ; metabolism ; Ischemia ; metabolism ; Male ; Molecular Chaperones ; metabolism ; Pressure Ulcer ; metabolism ; Rats ; Rats, Sprague-Dawley ; Subcutaneous Tissue ; blood supply

This study was aimed to investigate the sensitive index for predicting the sensitivity of patients with multiple myeloma (MM) to glucocorticoid (GC). MM1.S, MM1.R cell lines and 10 MM patients sensitive or non-sensitive to GC were enrolled in this study. The expression of heat shock protein 90 (HSP90) and P23 in peripheral blood mononuclear cells (PBMNC) of MM patients was detected by Western blot, and its relation with GC resistance was explored. The results showed that there were no differences in HSP90, GR and IκB-α expressions among MM1.S, MM1.R, PBMNC of normal persons and MM patients, while there was apparent difference in P23; along with increasing of dexamethasone dose, the survival rate of MM1.S decreased, but that of MM1.R did not change so obviously. Among 7 cases with P23 low expression, combination treatment scheme with GC was effective in 6 cases (86%), uneffective in 1 cases (14%); while among 3 cases with P23 high expression, 1 cases (33%) showed effective to combination treatment with GC, 2 cases (67%) showed uneffective (P < 0.05). It is concluded that the P23 expression may predict the sensitivity of MM patients to GC and may be used as index for guiding clinical treatment.
Aged ; Aged, 80 and over ; Female ; Glucocorticoids ; pharmacology ; therapeutic use ; HSP90 Heat-Shock Proteins ; metabolism ; Humans ; Male ; Middle Aged ; Molecular Chaperones ; metabolism ; Multiple Myeloma ; diagnosis ; drug therapy ; metabolism ; Phosphoproteins ; metabolism ; Tumor Cells, Cultured

As a large family of hydrolases, GTPases are widespread in cells and play the very important biological function of hydrolyzing GTP into GDP and inorganic phosphate through binding with it. GTPases are involved in cell cycle regulation, protein synthesis, and protein transportation. Chaperones can facilitate the folding or refolding of nascent peptides and denatured proteins to their native states. However, chaperones do not occur in the native structures in which they can perform their normal biological functions. In the current study, the chaperone activity of the conserved GTPases of Escherichia coli is tested by the chemical denaturation and chaperone-assisted renaturation of citrate synthase and α-glucosidase. The effects of ribosomes and nucleotides on the chaperone activity are also examined. Our data indicate that these conserved GTPases have chaperone properties, and may be ancestral protein folding factors that have appeared before dedicated chaperones.
Citrate (si)-Synthase ; chemistry ; Cloning, Molecular ; Conserved Sequence ; Escherichia coli ; cytology ; enzymology ; GTP Phosphohydrolases ; chemistry ; genetics ; isolation & purification ; metabolism ; Guanosine Diphosphate ; pharmacology ; Guanosine Triphosphate ; analogs & derivatives ; pharmacology ; Molecular Chaperones ; chemistry ; genetics ; isolation & purification ; metabolism ; Protein Denaturation ; drug effects ; Protein Renaturation ; drug effects ; Ribosomes ; metabolism ; alpha-Glucosidases ; chemistry

Proteins fold into their functional 3-dimensional structures from a linear amino acid sequence. In vitro this process is spontaneous; while in vivo it is orchestrated by a specialized set of proteins, called chaperones. Protein folding is an ongoing cellular process, as cellular proteins constantly undergo synthesis and degradation. Here emerging links between this process and cancer are reviewed. This perspective both yields insights into the current struggle to develop novel cancer chemotherapeutics and has implications for future chemotherapy discovery.
Amino Acid Sequence ; Heat-Shock Proteins ; metabolism ; Homeostasis ; Humans ; Molecular Chaperones ; chemistry ; metabolism ; Molecular Targeted Therapy ; Neoplasms ; drug therapy ; metabolism ; Protein Folding ; Proteins ; chemistry ; metabolism ; Proteolysis