OBJECTIVETo investigate the effect of dentin phosphoprotein (DPP) in inducing dentinal mineralization.

METHODSHuman DPP was combined with EAH-Sepharose 4B beads and its function of inducing mineralization was studied in mineralization system in-vitro. The mineral formed on the surface of the beads was analyzed by scanning electron microscopy (SEM) and the structure was analyzed by X-ray diffraction and plasma emission spectrum.

RESULTSThere was mineral formed on the beads with combined DPP and the mineral was calcium phosphates whose ratio of calcium to phosphate was 1.33. The diffractogram of the formed mineral was more similar to hydroxyapatite than to other calcium phosphates.

CONCLUSIONWhen tightly combined with certain support substance, human DPP can induce mineralization.

Calcium Phosphates ; chemistry ; metabolism ; Dentin ; chemistry ; metabolism ; Dentinogenesis ; Humans ; Microscopy, Electron, Scanning ; Minerals ; chemistry ; metabolism ; Phosphoproteins ; chemistry ; metabolism ; Tooth Calcification ; X-Ray Diffraction

OBJECTIVETo investigate the effect of removing EDTA-soluble phosphate protein in dentin on the later remineralization for the purpose of better understanding of mechanism of dentin phosphate proteins on dentin mineralization.

METHODSTo remove soluble phosphate protein by EDTA dissolution, then the remineralization rate was monitored by a constant composition crystal growth technique. The results were compared with those from the normal dentin and the dentin partially demineralized by acetic acid.

RESULTSFaster remineralization rates were found with dentin demineralized by EDTA (0.5 and 2 h) compared with normal dentin powder, while a slower rate was found with dentin demineralized by acetic acid. The increase of remineralization rate by removing phosphate protein from dentin was 100% more at 200 min after the start of the reaction.

CONCLUSIONEDTA-soluble phosphate protein in dentin has a great potential to inhibit remineralization.

Dental Cementum ; chemistry ; metabolism ; Dentin ; chemistry ; Edetic Acid ; Humans ; Phosphoproteins ; analysis ; physiology ; Tooth Demineralization ; metabolism ; Tooth Remineralization

Recently, the gene encoding clathrin assembly protein of lymphoid myeloid leukemia (CALM), which is homologous to the AP180, was cloned from rat brain, and its expression differential to AP180 was reported (Kim and Lee, 1999). This gene product promotes the polymerization of clathrin into clathrin cage and found to be a regulator in membrane trafficking between intracellular compartments in eukaryotic cells (Kim et al., 2000). In this study, we have purified the CALM protein from clathrin-coated vesicles of rat liver using the monoclonal antibody against the recombinant N-terminal region of the CALM. The coated proteins extracted from the coated vesicle fraction was further purified by multi-step procedures involving gel-filtration and ion-exchange chromatography and SDS-PAGE. The purified protein with an apparent molecular weight of 100 kD promoted the assembly of clathrin triskelia into clathrin cage. In this respect the CALM protein bears a functional resemblance to the AP180 that has been previously described.
Animal ; Clathrin/*metabolism ; Clathrin-Coated Vesicles/*chemistry ; Liver/*chemistry ; Nerve Tissue Proteins/*isolation & purification ; Phosphoproteins/*isolation & purification ; Rats

OBJECTIVETo investigate the anti-atherosclerosis mechanism of Astragalus mongholicus polysaccharides (APS) by examining its effect on gene expression profiles of the dendritic cells (DCs) from healthy donors.

METHODSPeripheral blood DCs from healthy donors were incubated with 200 mg/L APS overnight, and changes in the gene expression profiles were investigated using microarray technique and RT-PCR.

RESULTSCompared with the control cells, APS-treated DCs showed significantly up-regulated expressions of CD36 (0.97 ± 0.23 vs 5.45 ± 1.14) and IL-27 (1.08 ± 0.22 vs 2.97 ± 0.61) and down-regulated expression of expression of IFI16 (0.98 ± 0.18 vs 0.46 ± 0.11).

CONCLUSIONSAPS can promote the maturation and differentiation of DCs by up-regulating CD36 and IL-27 and down-regulating IFI16, and thus positively affects the occurrence and progression of the atherosclerosis.

Astragalus Plant ; chemistry ; CD36 Antigens ; metabolism ; Cell Differentiation ; Dendritic Cells ; drug effects ; Humans ; Interleukins ; metabolism ; Nuclear Proteins ; metabolism ; Phosphoproteins ; metabolism ; Polysaccharides ; pharmacology ; Transcriptome

Clathrin-coated vesicles (CCVs) are involved in protein and lipid trafficking between intracellular compartments in eukaryotic cells. CCVs are composed of clathrin and assembly proteins. The clathrin assembly protein lymphoid myeloid leukemia (CALM) gene, encodes a homologoue of the neuronal clathrin assembly protein AP180. In this study, we characterized the properties of the CALM expressed in E. coli. The molecular weight of bacterially expressed GST-CALM fusion protein was approximately 105 kD on SDS-PAGE. The CALM protein could promote clathrin triskelia into clathrin cages and could bind the preformed clathrin cage. However, 33 kD N-terminal domain of CALM could not bind pre-assembled clathrin cages, but assemble clathrin triskelia into clathrin cages. The CALM protein was bound to SH3 domain through N-terminal domain1, in vitro. The CALM protein is proteolyzed by caspase 3, caspase 8 and calpain through C-terminal domain.
Animal ; Antibodies, Monoclonal ; Calpain/chemistry ; Caspases/chemistry ; Clathrin-Coated Vesicles/metabolism* ; Electrophoresis, Polyacrylamide Gel ; Escherichia coli/metabolism ; Escherichia coli/genetics ; Female ; Glutathione Transferase/genetics* ; Mice ; Mice, Inbred BALB C ; Nerve Tissue Proteins/metabolism ; Nerve Tissue Proteins/metabolism ; Nerve Tissue Proteins/chemistry* ; Phosphoproteins/metabolism ; Phosphoproteins/genetics ; Phosphoproteins/chemistry* ; Protein Binding ; Rabbits ; Recombinant Fusion Proteins/metabolism ; Recombinant Fusion Proteins/genetics ; Recombinant Fusion Proteins/chemistry* ; src Homology Domains

Coronaviruses are the causative agent of respiratory and enteric diseases in animals and humans. One example is SARS, which caused a worldwide health threat in 2003. In coronaviruses, the structural protein N (nucleocapsid protein) associates with the viral RNA to form the filamentous nucleocapsid and plays a crucial role in genome replication and transcription. The structure of N-terminal domain of MHV N protein also implicated its specific affinity with transcriptional regulatory sequence (TRS) RNA. Here we report the crystal structures of the two proteolytically resistant N- (NTD) and C-terminal (CTD) domains of the N protein from murine hepatitis virus (MHV). The structure of NTD in two different crystal forms was solved to 1.5 Å. The higher resolution provides more detailed structural information than previous reports, showing that the NTD structure from MHV shares a similar overall and topology structure with that of SARS-CoV and IBV, but varies in its potential surface, which indicates a possible difference in RNA-binding module. The structure of CTD was solved to 2.0-Å resolution and revealed a tightly intertwined dimer. This is consistent with analytical ultracentrifugation experiments, suggesting a dimeric assembly of the N protein. The similarity between the structures of these two domains from SARS-CoV, IBV and MHV corroborates a conserved mechanism of nucleocapsid formation for coronaviruses.
Amino Acid Sequence ; Binding Sites ; Crystallography, X-Ray ; Molecular Sequence Data ; Murine hepatitis virus ; chemistry ; metabolism ; Nucleocapsid Proteins ; chemistry ; metabolism ; Phosphoproteins ; chemistry ; metabolism ; Protein Binding ; Protein Folding ; Protein Multimerization ; Protein Structure, Secondary ; Protein Structure, Tertiary ; RNA ; metabolism ; Sequence Alignment

In recent years, human cancer genome projects provide unprecedented opportunities for the discovery of cancer genes and signaling pathways that contribute to tumor development. While numerous gene mutations can be identified from each cancer genome, what these mutations mean for cancer is a challenging question to address, especially for those from less understood putative new cancer genes. As a powerful approach, in silico bioinformatics analysis could efficiently sort out mutations that are predicted to damage gene function. Such an analysis of human large tumor suppressor genes, LATS1 and LATS2, has been carried out and the results support a role of hLATS1//2 as negative growth regulators and tumor suppressors.
Adaptor Proteins, Signal Transducing ; chemistry ; metabolism ; Animals ; Carrier Proteins ; chemistry ; metabolism ; Computational Biology ; Genes, Neoplasm ; Humans ; LIM Domain Proteins ; chemistry ; metabolism ; Mice ; Mutation ; Neoplasms ; genetics ; pathology ; Phosphoproteins ; chemistry ; metabolism ; Phosphorylation ; Protein Binding ; Protein Structure, Tertiary ; Protein-Serine-Threonine Kinases ; chemistry ; genetics ; metabolism ; Transferases (Other Substituted Phosphate Groups) ; chemistry ; metabolism ; Tumor Suppressor Proteins ; chemistry ; genetics ; metabolism

This work was mainly studied the effects of the four alkaloids from Coptidis Rhizoma on the mouse peritoneal macrophages in vitro and preliminarily discussed the regulating mechanisms. The effect of alkaloids from Coptidis Rhizoma on the vitality of macrophages was measured by the MTT assay. The effect of alkaloids on the phagocytosis of macrophages was determined by neutral red trial and respiratory burst activity was tested by NBT. The expressions of respiratory-burst-associated genes influenced by alkaloids were detected by qRT-PCR. The conformation change of membrane protein in macrophages by the impact of alkaloids was studied by fluorospectro-photometer. Results showed that the four alkaloids from Coptidis Rhizoma could increase the phagocytosis of macrophages in different level and berberine had the best effect. Berberine, coptisine and palmatine had up-regulation effects on respiratory burst activity of mouse peritoneal macrophages stimulated by PMA and regulatory activity on the mRNA expression of PKC, p40phox or p47phox, whereas the epiberberine had no significant influence on respiratory burst. Moreover, alkaloids from Coptidis Rhizoma could change the conformation of membrane protein and the berberine showed the strongest activity. The results suggested that the four alkaloids from Coptidis Rhizoma might activate macrophages through changing the conformation of membrane protein of macrophages and then enhanced the phagocytosis and respiratory burst activity of macrophages. Furthermore, the regulatory mechanism of alkaloids on the respiratory burst activity of macrophages may be also related to the expression level of PKC, p40phox and p47phox.
Alkaloids ; pharmacology ; Animals ; Cells, Cultured ; Coptis ; chemistry ; Drugs, Chinese Herbal ; pharmacology ; Female ; Gene Expression ; drug effects ; Macrophages, Peritoneal ; drug effects ; Mice ; Phosphoproteins ; genetics ; metabolism ; Protein Kinase C ; genetics ; metabolism ; Rhizome ; chemistry

To compare the stem niche in different culture conditions of limbal epithelial cells, the suspended human limbal epithelial cells (HLECs) were seeded on the 3T3-pretreated plates and the other suspended cells were plated on amniotic membranes (AMs) which were either cryo-preserved or freeze-dried. All were cultured for 10 to 12 days. Reverse transcription-polymerase chain reaction (RT-PCR) for ATP-binding casette, subfamily G, member 2 (ABCG2), p63, cytokeratin 12, and connexin 43 were performed in cultivated HLECs and their expression levels were compared. The mRNA expression of all markers examined showed no statistically significant differences between the cells on cryo-preserved and on freeze-dried AM. The expression of p63 and cytokeratin 12 in cultivated cells on AMs were significantly lower than those in 3T3-cocultured cells on RT-PCR and immunofluorescent staining. Cultivated HLECs on AMs showed reduced proliferation and differentiation while maintaining stem-property regardless of the preservative method of AM.
3T3 Cells ; Animals ; Cell Culture Techniques/*instrumentation/*methods ; Cells, Cultured ; Cytological Techniques ; DNA Primers/chemistry ; Epithelial Cells/*metabolism ; Humans ; Immunohistochemistry/methods ; Keratin-12/metabolism ; Mice ; Models, Biological ; Phosphoproteins/metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Stem Cells/cytology ; Trans-Activators/metabolism

Endocytosis is differentially regulated by hypoxia-inducible factor-1alpha (HIF-1alpha) and phospholipase D (PLD). However, the relationship between HIF-1alpha and PLD in endocytosis is unknown. HIF-1alpha is degraded through the prolyl hydroxylase (PHD)/von Hippel-Lindau (VHL) ubiquitination pathway in an oxygen-dependent manner. Here, we show that PLD1 recovers the decrease in epidermal growth factor receptor (EGFR) endocytosis induced by HIF-1alpha independent of lipase activity via the Rab5-mediated endosome fusion pathway. EGF-induced interaction of PLD1 with HIF-1alpha, PHD and VHL may contribute to EGFR endocytosis. The pleckstrin homology domain (PH) of PLD1 itself promotes degradation of HIF-1alpha, then accelerates EGFR endocytosis via upregulation of rabaptin-5 and suppresses tumor progression. These findings reveal a novel role of the PLD1-PH domain as a positive regulator of endocytosis and provide a link between PLD1 and HIF-1alpha in the EGFR endocytosis pathway.
Animals ; Blood Proteins/chemistry/*metabolism ; Endocytosis ; Female ; HEK293 Cells ; HT29 Cells ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit/metabolism ; Mice, Nude ; Neoplasms/genetics/metabolism/pathology ; Phospholipase D/chemistry/*metabolism ; Phosphoproteins/chemistry/*metabolism ; Protein Structure, Tertiary ; Receptor, Epidermal Growth Factor/*metabolism ; Signal Transduction ; *Up-Regulation ; Vesicular Transport Proteins/*genetics/metabolism ; rab5 GTP-Binding Proteins/*metabolism