Animals ; PrPSc Proteins ; metabolism ; pathogenicity ; Prion Diseases ; transmission ; Prions ; physiology

Doppel protein (abbreviation Dpl) is a newly recognized Glycosyl phosphatidyl inositol (GPI) anchored and highly glycosylated protein, which is similar to prion protein (PrP) in the chemical structure. The encoding gene of Dpl named PRND locates at the downstream of the prion protein gene (PRNP). These two proteins are different in physiological functions. The expression of Dpl focuses on testis tissue at the adult, and takes an important role in maintaining sperm integrality, normal fertility, and motion ability. We reviewed the biological characters, physiological functions of Dpl and its effects on male reproduction in order to provide theory guidance for the study on physiological function and male reproduction controlling.
Animals ; GPI-Linked Proteins ; Humans ; Male ; Prions ; metabolism ; physiology ; Reproduction ; physiology ; Testis ; growth & development ; metabolism

Animals ; China ; epidemiology ; Humans ; Prevalence ; Prion Diseases ; epidemiology ; metabolism ; prevention & control ; Prions ; metabolism

In order to explore the potential influences of the disulfide bridge on the physical and chemical properties of PrP protein, the expressed recombinant human wild-type PrP protein was purified for using in an established redox process for the reduction and oxidation of the ethanethiol group within PrP. Sedimentation tests illustrated that redox process remarkably promoted the aggregation of recombinant PrP. Thioflavin T binding assay revealed an enhanced fibrillization of the recombinant human PrP after redox process. Far-UV circular dichroism demonstrated that the PrP treated with redox process showed a significant p-sheet rich structure. Furthermore, PrP-specific Western blot identified that the recombinant PrP after redox possessed stronger proteinase K-resistance. Those data indicates that the formation of the disulfide bridge induces the alteration of the secondary structure and enhances the progresses of aggregation and fibrillization of PrP protein.
Amyloid ; chemistry ; Endopeptidase K ; metabolism ; Humans ; Oxidation-Reduction ; Prions ; chemistry ; metabolism ; Protein Multimerization ; Protein Structure, Secondary ; Proteolysis ; Sulfhydryl Compounds ; chemistry

To investigate changes of 14-3-3beta from apoptosis induced by PrP106-126 polypeptide, HeLa cell was incubated with PrP106-126 for 4h or 8h. Nucleus changes and the expression of PARP were detected differently by Hoechst staining and Western blotting. Expressing of protein and mRNA from 14-3-3beta was determined by Western blotting and Real-time PCR. The results show that typical nucleus pyknosis and chip of apoptosis and degradation of PARP were induced by PrP106-126 peptide in HeLa cells. Degradation of 14-3-3beta appeared in apoptosis groups induced by PrP106-126 peptide. However, 14-3-3beta mRNA did not display any changes in apoptosis groups. This study indicated that degradation of antiapoptosis protein 143-3beta induced by PrP106-126 peptide may be one of pathogenesis mechanism of prion disease.
14-3-3 Proteins ; metabolism ; Apoptosis ; drug effects ; HeLa Cells ; Humans ; Peptide Fragments ; pharmacology ; Prions ; pharmacology ; Proteolysis ; drug effects

Misfolded isoform of prion protein (PrP), termed scrapie PrP (PrP(Sc)), tends to aggregate into various fibril forms. Previously, we reported various conditions that affect aggregation of recombinant PrP into amyloids. Because amyloidogenesis of PrP is closely associated with transmissible spongiform encephalopathies such as Creutzfeldt-Jakob disease in humans, we investigated infectivity of recombinant PrP amyloids generated in vitro. Using cultured cell lines which overexpress cellular PrP of different species, we measured the level of de novo synthesized PrP(Sc) in cells inoculated with recombinant mouse PrP amyloids. While PrP-overexpressing cells were susceptible to mouse-adapted scrapie prions used as the positive control, demonstrating the species barrier effect, infection with amyloids made of truncated recombinant PrP (PrP[89-230]) failed to form and propagate PrP(Sc) even in the cells that express mouse cellular PrP. This suggests that infectivity of PrP amyloids generated in vitro is different from that of natural prions. Recombinant PrP (89-230) amyloids tested in the current study retain no or a minute level, if any, of prion infectivity.
Animals ; Cell Line ; Kidney/*metabolism/*pathology ; Mice ; PrPSc Proteins/*metabolism ; Prion Diseases/*metabolism/*pathology ; Prions/*metabolism ; Rabbits ; Recombinant Proteins/*metabolism ; Up-Regulation

OBJECTIVETo examine Prion protein(PrP) expression and its clinical significance in oral mucosa, oral leukoplakia, oral squamous cell carcinoma(OSCC) and its subgroups.

METHODSExpression of PrP in OSCC, oral leukoplakia and mucosa specimen was detected by immunohistochemistry. The association between the expression and gender, TNM clinical stages, pathological grades was evaluated.

RESULTSThe positive expression rate of PrP in normal, oral leukoplakia and OSCC tissues was 15% (3/20) , 42% (11/26) and 95% (80/84) , respectively. There was a significant difference between the expression of PrP in leukoplakia and in high, moderately and poorly differentiated OSCC(P < 0.05). The positive expression rate was increased with the declining of pathological differentiation (P < 0.05). There was no significant difference in PrP expression among lymph node metastasis and gender. PrP expression of stages I and II was up-regulated with the decreased differentiation (P < 0.05). There was no significant difference in PrP expression between stage III and IV (P > 0.05). Between stages I+II and III+IV in the overa II expression of PrP, there was a significant difference(P < 0.05).

CONCLUSIONSThe high expression of PrP in OSCC and the progressive expression from leukoplakia to OSCC was closely related to the carcinogenesis of OSCC, pathologic stage and clinical TNM stage.

Carcinoma, Squamous Cell ; metabolism ; pathology ; Cell Differentiation ; Female ; Humans ; Leukoplakia, Oral ; metabolism ; pathology ; Lymphatic Metastasis ; Male ; Mouth Mucosa ; metabolism ; Mouth Neoplasms ; metabolism ; pathology ; Neoplasm Staging ; Prions ; metabolism

Cellular prion protein, a membrane protein, is expressed in all mammals. Prion protein is also found in human blood as an anchorless protein, and this protein form is one of the many potential sources of misfolded prion protein replication during transmission. Many studies have suggested that beta-amyloid1-42 oligomer causes neurotoxicity associated with Alzheimer's disease, which is mediated by the prion protein that acts as a receptor and regulates the hippocampal potentiation. The prevention of the binding of these proteins has been proposed as a possible preventative treatment for Alzheimer's disease; therefore, a greater understanding of the binding hot-spots between the two molecules is necessary. In this study, the epitope mapping immunoassay was employed to characterize binding epitopes within the prion protein and complementary epitopes in beta-amyloid. Residues 23-39 and 93-119 in the prion protein were involved in binding to beta-amyloid1-40 and 1-42, and monomers of this protein interacted with prion protein residues 93-113 and 123-166. Furthermore, beta-amyloid antibodies against the C-terminus detected bound beta-amyloid1-42 at residues 23-40, 104-122 and 159-175. beta-Amyloid epitopes necessary for the interaction with prion protein were not determined. In conclusion, charged clusters and hydrophobic regions of the prion protein were involved in binding to beta-amyloid1-40 and 1-42. The 3D structure appears to be necessary for beta-amyloid to interact with prion protein. In the future, these binding sites may be utilized for 3D structure modeling, as well as for the pharmaceutical intervention of Alzheimer's disease.
Amyloid beta-Peptides/*metabolism ; Electrophoresis ; Enzyme-Linked Immunosorbent Assay ; *Epitope Mapping ; Epitopes/*metabolism ; Humans ; *Immunoassay ; Prions/*metabolism ; Protein Binding ; Recombinant Proteins/metabolism

UNLABELLEDOBJECTIVE To study the potential interaction between PrP protein.

METHODSThe supernatant of health and scrapie-infected hamsters' brain homogenate was prepared, while various recombinant 14-3-3beta or PrP proteins were purified. The possible molecular interaction between 14-3-3beta proteins and PrP was tested by pull-down and immunoprecipitation assays.

RESULTSBoth native PrP(c) and its protease-resistant isoform (PrP(Sc)) formed complexes with 14-3-3beta. The full-length recombinant 14-3-3beta proteins interacted with PrP. The domain responsible for interacting 14-3-3beta was located at N-terminal of 14-3-3beta (residues 1 to 38).

CONCLUSIONThe studies of the association of PrP with 14-3-3beta may further provide insight into a potential role of 14-3-3beta in the biological function of PrP and the pathogenesis of prion disease.

14-3-3 Proteins ; metabolism ; Animals ; Binding Sites ; Brain Chemistry ; Cricetinae ; Endopeptidases ; metabolism ; PrPSc Proteins ; metabolism ; Prion Diseases ; pathology ; Prions ; metabolism ; Scrapie ; physiopathology

OBJECTIVETo study the potential interaction between PrP protein and glial fibrillary acidic protein (GFAP) and identify the binding region within PrP with GFAP.

METHODSThe supernatant of healthy and scrapie-infected hamsters' brain homogenate was prepared, while various recombinant PrP or GFAP proteins were expressed using prokaryotic-expressing or in-vitro translation system. The possible molecular interaction between PrP proteins and GFAP was tested by Pull-down and immunoprecipitation assays.

RESULTSBoth native PrP(C) and its protease-resistant isoform (PrP(Sc)) formed complexes with the native GFAP. The full-length recombinant PrP proteins interacted with GFAP. The domain responsible for interacting GFAP was located at C-terminal of PrP (residues 91 to 231).

CONCLUSIONThe studies of the association of PrP with GFAP may further provide insight into a potential role of GFAP in the biological function of PrP and the pathogenesis of prion disease.

Animals ; Brain ; metabolism ; Cricetinae ; Gene Deletion ; Glial Fibrillary Acidic Protein ; genetics ; metabolism ; Immunoprecipitation ; Mice ; Prions ; genetics ; metabolism ; Protein Binding ; Recombinant Proteins ; metabolism