Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q9UIJ5 (Rec)
 58,342 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Some children with juvenile hypothyroidism exhibit unexplained precocious puberty. Interaction of TSH with the human FSH receptor (hFSH-R) is a possible pathophysiological mechanism for this syndrome that has not been explored due to the lack of hFSH-free TSH preparations and the scarcity of a suitable hFSH-R-based assay system. To devise an in vitro FSH bioassay suitable for exploring this mechanism, we expressed hFSH-R complementary DNA in COS-7 cells and stimulated them with recombinant hTSH (rec-hTSH). Rec-hTSH elicited a dose-dependent cAMP response in the in vitro hFSH-R bioassay; however, the concentration of rec-hTSH required for half-maximal stimulation was several logs greater than that of hFSH. Rec-hTSH acted as a competitive inhibitor of hFSH at the hFSH-R, indicating that hTSH and hFSH are acting through the same receptor, namely the hFSH-R. This provides a potential novel mechanism for the precocious puberty of juvenile hypothyroidism.
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PMID:A potential novel mechanism for precocious puberty in juvenile hypothyroidism. 762 56

Developing methods for in vitro synthesis of the carbohydrate structure Galalpha1-3Galbeta1-4GlcNAc-R (termed the alpha-galactosyl epitope) on human tumour cells may be of potential clinical significance in cancer immunotherapy. Tumour vaccines with this epitope would be opsonized in vivo by the natural anti-Gal antibody, which is present in large amounts in humans, and which interacts specifically with alpha-galactosyl epitopes. Binding of anti-Gal to alpha-galactosyl epitopes on tumour cell membranes is likely to increase uptake of the cell membranes by antigen-presenting cells, such as macrophages, via the adhesion of the Fc portion of anti-Gal to Fc receptors on these cells. This, in turn, may increase processing and presentation of tumour-associated antigens by antigen-presenting cells, and induce an effective immune response against tumour cells with these antigens. The present study describes a method for the synthesis of alpha-galactosyl epitopes on human cells (red cells used as a model) by recombinant alpha1,3galactosyltransferase (rec. alpha1,3GT) expressed in bacteria. Escherichia coli was transformed with cDNA of the luminal portion of New World monkey rec. alpha1,3GT linked to six histidines (His)6 at the N-terminus. The enzyme produced by the bacteria was isolated from bacterial lysates on a nickel-Sepharose column and eluted with imidazole. This recombinant enzyme displayed acceptor specificity similar to that of rec. alpha1,3GT produced in COS cells. Red cells were pre-treated with sialidase for exposure of N-acetyllactosamine acceptors, then subjected to rec. alpha1,3GT activity. This enzyme synthesized at least 4 x 10(4) alpha-galactosyl epitopes/red cell. These epitopes were found to be accessible for binding of anti-Gal, as well as Bandeiraea simplicifolia IB4 lectin. It is argued that the method presented can be used for the synthesis of alpha-galactosyl epitopes on membranes of autologous tumour vaccines in humans.
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PMID:alpha-galactosyl (Galalpha1-3Galbeta1-4GlcNAc-R) epitopes on human cells: synthesis of the epitope on human red cells by recombinant primate alpha1,3galactosyltransferase expressed in E.coli. 872 75

The mitochondrial outer membrane enzyme kynurenine 3-hydroxylase (K3H) is an NADPH-dependent flavin mono-oxygenase involved in the tryptophan pathway, where it catalyzes the hydroxylation of kynurenine. K3H was transiently expressed in COS-1 cells as a glutathione S-transferase (GST) fusion protein, and the pure recombinant protein (rec-K3H) was obtained with a specific activity of about 2000 nmol.min-1.mg-1. Rec-K3H was shown to have an optimum pH at 7.5, to use NADPH more efficiently than NADH, and to contain one molecule of non-covalently bound FAD per molecule of enzyme. The mechanism of the rec-K3H-catalyzed reaction was investigated by overall initial-rate measurements, and a random mechanism in which combination of the enzyme with one substrate does not influence its affinity for the other is proposed. Further kinetic studies revealed that K3H activity was inhibited by both pyridoxal phosphate and Cl-, and that NADPH-catalyzed oxidation occurred even in the absence of kynurenine if 3-hydroxykynurenine was present, suggesting an uncoupling effect of 3-hydroxykynurenine with peroxide formation. This observation could be of clinical interest, as peroxide formation could explain the neurotoxicity of 3-hydroxykynurenine in vivo.
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PMID:Functional characterization and mechanism of action of recombinant human kynurenine 3-hydroxylase. 1067 18

C2 is a serum glycoprotein that is essential for activation of the classical and lectin pathways of the complement system. We reported previously that in transiently transfected COS cells, C2 accumulates in the endoplasmic reticulum-Golgi intermediate compartment (ERGIC). Transfection with a cDNA corresponding to a variant C2 mRNA in which exon 17 is spliced out, C2Delta(17), resulted in retention of the mutant polypeptide in the ER. We now show that calnexin, a lectin-like chaperone, colocalizes with wild-type (wt) C2 and C2Delta(17). Biosynthetic labeling and sequential immunoprecipitation experiments indicated that colocalization is due to a physical association between calnexin and C2. Immunofluorescence analysis indicated that calnexin was upregulated in cells transfected with either C2 species. Upregulation of calnexin was not affected by castanospermine, which inhibits glucosidases I and II. However, castanospermine inhibited translocation of calnexin to the ERGIC in wt C2 transfected cells. Upregulation of calnexin was also observed in cells transfected with the complement protein factor B, a glycoprotein with extensive structural and functional similarities to C2, but not in cells transfected with complement proteins C3 or factor D, which have no structural similarity to C2, and low or no glycan content, respectively. Calnexin upregulation by transfection with C2 or factor B, but not factor D, was also demonstrated by quantitative analysis of calnexin immunoprecipitates from biosynthetically labeled cells. Increased calnexin expression by overexpressed C2 and factor B appears to be triggered either by the high glycan content of these proteins or, since it also occurs in the presence of castanospermine, by shared features of the structure of these two proteins.
Anat Rec 2002 May 01
PMID:Calnexin is associated with and induced by overexpressed human complement protein C2. 1198 87