Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038362 (stomatitis)
 8,852 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Expressed sequence tags coding for a potential SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) were revealed during data base searches. The deduced amino acid sequence of the complete coding region predicts a 217-residue protein with a COOH-terminal hydrophobic membrane anchor. Affinity-purified antibodies raised against the cytoplasmic region of this protein specifically detect a 29-kilodalton integral membrane protein enriched in the Golgi membrane. Indirect immunofluorescence microscopy reveals that this protein is mainly associated with the Golgi apparatus. When detergent extracts of the Golgi membrane are incubated with immobilized glutathione S-transferase alpha soluble N-ethylmaleimide-sensitive factor attachment protein (GST-alpha-SNAP), this protein was specifically retained. This protein has been independently identified and termed Vti1-rp2, and it is homologous to Vti1p, a yeast Golgi SNARE. We further show that Vti1-rp2 can be qualitatively coimmunoprecipitated with Golgi syntaxin 5 and syntaxin 6, suggesting that Vti1-rp2 exists in at least two distinct Golgi SNARE complexes. In cells microinjected with antibodies against Vti1-rp2, transport of the envelope protein (G-protein) of vesicular stomatitis virus from the endoplasmic reticulum to the plasma membrane was specifically arrested at the Golgi apparatus, providing further evidence for functional importance of Vti1-rp2 in protein trafficking in the secretory pathway.
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PMID:A 29-kilodalton Golgi soluble N-ethylmaleimide-sensitive factor attachment protein receptor (Vti1-rp2) implicated in protein trafficking in the secretory pathway. 970 16

Although all mammalian COPII components have now been cloned, little is known of their interactions with other regulatory proteins involved in exit from the endoplasmic reticulum (ER). We report here that a mammalian protein (Yip1A) that is about 31% identical to S. cerevisiae and which interacts with and modulates COPII-mediated ER-Golgi transport. Yip1A transcripts are ubiquitously expressed. Transcripts of a related mammalian homologue, Yip1B, are found specifically in the heart. Indirect immunofluorescence microscopy revealed that Yip1A is localized to vesicular structures that are concentrated at the perinuclear region. The structures marked by Yip1A co-localized with Sec31A and Sec13, components of the COPII coat protein complex. Immunoelectron microscopy also showed that Yip1A co-localizes with Sec13 at ER exit sites. Overexpression of the hydrophilic N terminus of Yip1A arrests ER-Golgi transport of the vesicular stomatitis G protein and causes fragmentation and dispersion of the Golgi apparatus. A glutathione S-transferase fusion protein with the hydrophilic N terminus of Yip1A (GST-Yip1A) is able to bind to and deplete vital components from rat liver cytosol that is essential for in vitro vesicular stomatitis G transport. Peptide sequence analysis of cytosolic proteins that are specifically bound to GST-Yip1A revealed, among other proteins, mammalian COPII components Sec23 and Sec24. A highly conserved domain at the N terminus of Yip1A is required for Sec23/Sec24 interaction. Our results suggest that Yip1A is involved in the regulation of ER-Golgi traffic at the level of ER exit sites.
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PMID:A membrane protein enriched in endoplasmic reticulum exit sites interacts with COPII. 1148 4

Oxysterol-binding protein (OSBP) is 1 of 12 related proteins implicated in the regulation of vesicle transport and sterol homeostasis. A yeast two-hybrid screen using full-length OSBP as bait was undertaken to identify partner proteins that would provide clues to the function of OSBP. This resulted in the cloning of vesicle-associated membrane protein-associated protein-A (VAP-A), a syntaxin-like protein implicated in endoplasmic reticulum (ER)/Golgi vesicle transport, and phospholipid regulation in mammalian cells and yeast, respectively. By using a combination of yeast two-hybrid, glutathione S-transferase pull-down and immunoprecipitation experiments, the VAP-A-binding region in OSBP was localized to amino acids 351-442. This region did not include the pleckstrin homology (PH) domain but overlapped with the N terminus of the oxysterol binding and OSBP homology domains. C- and N-terminal truncations or deletions of VAP prevented interaction with OSBP but did not affect VAP multimerization. Although the OSBP PH domain was not necessary for VAP-A binding in vitro, interaction with VAP-A was enhanced in cells by mutation of the conserved PH domain tryptophan (OSBP W174A) or deletion of the C-terminal half of the PH domain (OSBP Delta 132-182). OSBP W174A retained oxysterol binding activity, association with phospholipid vesicles via the PH domain, and localized with VAP in unusual ER-associated structures. At 40 degrees C, misfolded ts045-vesicular stomatitis virus G protein fused to green fluorescent protein was co-localized with VAP-A/OSBP W174A structures on the ER but was exported to the Golgi when folded normally at 32 degrees C. A fluorescent ceramide analogue also accumulated in these ER inclusions, and export to the Golgi was partially inhibited as indicated by decreased Golgi staining and a 30% reduction in sphingomyelin synthesis. These studies show that OSBP binding to the ER and Golgi apparatus is regulated by its PH domain and VAP interactions, and the complex is involved at a stage of protein and ceramide transport from the ER.
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PMID:Vesicle-associated membrane protein-associated protein-A (VAP-A) interacts with the oxysterol-binding protein to modify export from the endoplasmic reticulum. 1202 75

The TRAPP complex identified in yeast regulates vesicular transport in the early secretory pathway. Although some components of the TRAPP complex are structurally conserved in mammalian cells, the function of the mammalian components has not been examined. We describe our biochemical and functional analysis of mammalian Bet3, the most conserved component of the TRAPP complex. Bet3 mRNA is ubiquitously expressed in all tissues. Antibodies raised against recombinant Bet3 specifically recognize a protein of 22 kDa. In contrast to yeast Bet3p, the majority of Bet3 is present in the cytosol. To investigate the possible involvement of Bet3 in transport events in mammalian cells, we utilized a semi-intact cell system that reconstitutes the transport of the envelope glycoprotein of vesicular stomatitis virus (VSV-G) from the ER to the Golgi apparatus. In this system, antibodies against Bet3 inhibit transport in a dose-dependent manner, and cytosol that is immunodepleted of Bet3 is also defective in this transport. This defect can be rescued by supplementing the Bet3-depleted cytosol with recombinant GST-Bet3. We also show that Bet3 acts after COPII but before Rab1, alpha-SNAP and the EGTA-sensitive stage during ER-Golgi transport. Gel filtration analysis demonstrates that Bet3 exists in two distinct pools in the cytosol, the high-molecular-weight pool may represent the TRAPP complex, whereas the other probably represents the monomeric Bet3.
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PMID:Mammalian Bet3 functions as a cytosolic factor participating in transport from the ER to the Golgi apparatus. 1572 49

Human immunodeficiency virus type 1 (HIV-1) infection of human macrophages can be inhibited by antibodies which bind to the tetraspanin protein CD63, but not by antibodies that bind to other members of the tetraspanin family. This inhibitory response was limited to CCR5 (R5)-tropic virus and was only observed using macrophages, but not T cells. Here, we show that recombinant soluble forms of the large extracellular domain (EC2) of human tetraspanins CD9, CD63, CD81, and CD151 produced as fusion proteins with glutathione S-transferase (GST) can all potently and completely inhibit R5 HIV-1 infection of macrophages with 50% inhibitory concentration values of 0.11 to 1.2 nM. Infection of peripheral blood mononuclear cells could also be partly inhibited, although higher concentrations of EC2 proteins were required. Inhibition was largely coreceptor independent, as macrophage infections by virions pseudotyped with CXCR4 (X4)-tropic HIV-1 or vesicular stomatitis virus (VSV)-G glycoproteins were also inhibited, but was time dependent, since addition prior to or during, but not after, virus inoculation resulted in potent inhibition. Incubation with tetraspanins did not decrease CD4 or HIV-1 coreceptor expression but did block virion uptake. Colocalization of fluorescently labeled tetraspanin EC2 proteins and HIV-1 virions within, and with CD4 and CXCR4 at the cell surfaces of, macrophages could be detected, and internalized tetraspanin EC2 proteins were directed to vesicular compartments that contained internalized dextran and transferrin. Collectively, the data suggest that the mechanism of inhibition of HIV-1 infection by tetraspanins is at the step of virus entry, perhaps via interference with binding and/or the formation of CD4-coreceptor complexes within microdomains that are required for membrane fusion events.
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PMID:Recombinant extracellular domains of tetraspanin proteins are potent inhibitors of the infection of macrophages by human immunodeficiency virus type 1. 1677 36

The nucleocapsid (N) protein of nonsegmented negative-strand (NNS) RNA viruses, when expressed in eukaryotic cells, aggregates and forms nucleocapsid-like complexes with cellular RNAs. The phosphoprotein (P) has been shown to prevent such aggregation by forming a soluble complex with the N protein free from cellular RNAs (designated N(0)). The N(0)-P complex presumably mediates specific encapsidation of the viral genome RNA. The precise mechanism by which the P protein carries out this function remains unclear. Here, by using a series of deleted and truncated mutant forms of the P protein of vesicular stomatitis virus (VSV), Indiana serotype, we present evidence that the N-terminal 11 to 30 amino acids (aa) of the P protein are essential in keeping the N protein soluble. Furthermore, glutathione S-transferase fused to the N-terminal 40 aa by itself is able to form the N(0)-P complex. Interestingly, the N-terminal 40-aa stretch failed to interact with the viral genome N-RNA template whereas the C-terminal 72 aa of the P protein interacted specifically with the latter. With an in vivo VSV minigenome transcription system, we further show that a deletion mutant form of P (PDelta1-10) lacking the N-terminal 10 aa which is capable of forming the N(0)-P complex was unable to support VSV minigenome transcription, although it efficiently supported transcription in vitro in a transcription-reconstitution reaction when used as purified protein. However, the same mutant protein complemented minigenome transcription when expressed together with a transcription-defective P deletion mutant protein containing N-terminal aa 1 to 210 (PDeltaII+III). Since the minigenome RNA needs to be encapsidated before transcription ensues, it seems that the entire N-terminal 210 aa are required for efficient genome RNA encapsidation. Taking these results together, we conclude that the N-terminal 11 to 30 aa are required for N(0)-P complex formation but the N-terminal 210 aa are required for genome RNA encapsidation.
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PMID:Interaction of vesicular stomatitis virus P and N proteins: identification of two overlapping domains at the N terminus of P that are involved in N0-P complex formation and encapsidation of viral genome RNA. 1791 15

To explore the potential of a novel animal interferon formulation for controlled release, the yak interferon-alpha (IFN-alpha) glutathione S-transferase (GST) fusion protein was expressed in Escherichia coli (E. coli) and the purified recombinant IFN-alpha was encapsulated into solid lipid nanoparticles (SLN) by double emulsion solvent evaporation (w/o/w) method. The particle size and zeta potential of IFN-alpha-loaded SLN were 124.2+/-10.2 nm and -11.2+/-0.6 mV. The encapsulation efficiency of IFN-alpha and loading capacity of the SLN were 83.7+/-4.5% and 1.73+/-0.15%, respectively. In vitro release study and antiviral assay demonstrated that the IFN-alpha released from the SLN in a 16-day period exhibited antiviral activity in Madin-Darby bovine kidney (MDBK) cells against vesicular stomatitis virus (VSV), and showed a release pattern of an initial burst release followed by a sustained and slow release. Cytotoxicity assay in cell culture demonstrated that the SLN were not toxic. The results of this exploratory study suggest that the IFN-alpha-loaded SLN could be a useful formulation for controlled release in veterinary therapeutics.
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PMID:Yak interferon-alpha loaded solid lipid nanoparticles for controlled release. 1964 42

Rab31, a protein that we cloned from an oligodendrocyte cDNA library, is required for transport of mannose 6-phosphate receptors (MPRs) from the trans-Golgi network (TGN) to endosomes and for Golgi/TGN organization. Here we extend the knowledge of the mechanism of action of Rab31 by demonstrating its interaction with OCRL-1, a phosphatidylinositol 4,5-diphosphate 5-phosphatase (PI(4,5)P(2) 5-phosphatase) that regulates the levels of PI(4,5)P(2) and PI(4)P, molecules involved in transport and Golgi/TGN organization. We show that Rab31 interacts with OCRL-1 in a yeast two-hybrid system, GST-Rab31 pull-down experiments, and coimmunoprecipitation of OCRL-1 using oligodendrocyte culture lysates. Rab31 and OCRL-1 colocalize in the TGN, post-TGN carriers, and endosomes. Cation-dependent MPR (CD-MPR) is sorted to OCRL-1-containing carriers, but CD63 and vesicular stomatitis virus G (VSVG) are not. siRNA-mediated depletion of endogenous Rab31 causes collapse of the TGN apparatus and markedly decreases the levels of OCRL-1 in the TGN and endosomes. Our observations indicate that the role of Rab31 in the Golgi/TGN structure and transport of MPRs depends on its capability to recruit OCRL-1 to domains of the TGN where the formation of carriers occurs. The importance of our observations is highlighted by the fact that mutation of OCRL-1 causes demyelination in humans.
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PMID:Interaction of Rab31 and OCRL-1 in oligodendrocytes: its role in transport of mannose 6-phosphate receptors. 1979 75

Rabankyrin-5 (Rank-5) has been implicated as an effector of the small GTPase Rab5 and plays an important role in macropinocytosis. We have now identified Rank-5 as an interaction partner for the recycling regulatory protein, Eps15 homology domain 1 (EHD1). We have demonstrated this interaction by glutathione S-transferase-pulldown, yeast two-hybrid assay, isothermal calorimetry and co-immunoprecipitation, and found that the binding occurs between the EH domain of EHD1 and the NPFED motif of Rank-5. Similar to EHD1, we found that Rank-5 colocalizes and interacts with components of the retromer complex such as vacuolar protein sorting 26 (Vps26), suggesting a role for Rank-5 in retromer-based transport. Indeed, depletion of Rank-5 causes mislocalization of Vps26 and affects both the retrieval of mannose 6-phosphate receptor transport to the Golgi from endosomes and biosynthetic transport. Moreover, Rank-5 is required for normal retromer distribution, as overexpression of a wild-type Rank-5-small interfering RNA-resistant construct rescues retromer mislocalization. Finally, we show that depletion of either Rank-5 or EHD1 impairs secretion of vesicular stomatitis virus glycoprotein. Overall, our data identify a new interaction between Rank-5 and EHD1, and novel endocytic regulatory roles that include retromer-based transport and secretion.
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PMID:Rabankyrin-5 interacts with EHD1 and Vps26 to regulate endocytic trafficking and retromer function. 2228 51

In response to viral infection, the host innate antiviral response is elicited to limit viral replication. Many viruses have evolved various strategies to circumvent the host antiviral response. It has been reported that matrix (M) protein of vesicular stomatitis virus (VSV) can inhibit host gene expression to evade the host innate immune response. However, the molecular mechanism remains unclear. Here, we demonstrated that VSV M protein inhibited transcription of a reporter gene transfected into BSR-T7/5 cells. To further investigate the underlying mechanism, a yeast two-hybrid screen was performed to search for host proteins that interact with the M protein. The subunit of transcription/repair factor TFIIH, p8, was identified as an M binding partner, and the interaction was validated with a GST pull-down assay and laser confocal microscopy. Through a mutagenesis analysis, we found that the p8-M interaction was impaired when I96, E156, R159 and R160 residues on M were replaced with Ala. These mutants reduced the inhibitory effect on transcription of the reporter gene. Furthermore, the transcription inhibition mediated by M was impaired when co-expressed with p8. These results indicate that the p8-M interaction plays an important role in inhibiting transcription of host genes.
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PMID:The matrix protein of vesicular stomatitis virus inhibits host-directed transcription of target genes via interaction with the TFIIH subunit p8. 2888 55


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