Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated accessory cell function, antigen (Ag) trafficking, and uptake of immune complexes in isolated nasal epithelial cells (NEC) and airway epithelial cells (AEC), as well as in the two respiratory epithelial cell lines A549 and BEAS-2B. The NEC and AEC were capable of supporting Ag-specific as well as phytohemagglutinin-induced and anti-CD3 antibody-induced T-cell proliferation. We colocalized fluorescein isothiocyanate (FITC)-labeled Ags with human leukocyte antigen (HLA)-DR in A549 and BEAS-2B, utilizing laser confocal microscopy. Respiratory epithelial cells stimulated and unstimulated with interferon (IFN)-gamma were pulsed with FITC-labeled Ags for varying periods and evaluated for their ability to internalize Ag. In the unstimulated cells, intracellular punctate staining was evident at 60 min and persisted up to 120 min. In the IFN-gamma-stimulated cells (100 U/ml for 48 h), uptake occurred at 30 min, was maximal at 60 min, and diminished at 120 min. We conducted kinetic studies in the A549 and BEAS-2B cells, utilizing electron microscopy with colloidal gold-conjugated Ags (Au-OVA). At 15 min, Au-OVA was evident in the early compartments resembling the compartment of uncoupling of receptor and ligand. At 30 min, multivesicular bodies were labeled with Au-OVA, and by 60 min Au-OVA was present in the primary and secondary lysosomes. The FITC-labeled Ags colocalized with an early endosomal marker (anti-cathepsin D), a late endosomal marker (M6PR), a lysosomal marker (CD63), and with 3-(2, 4-dinitroanilino)-3'-aminomethyldipropylamine, a marker of acidic vesicles. The BEAS-2B and A549 cells, and NEC and AEC, expressed surface Fcgamma receptor and internalized IgG immune complexes. The NEC and AEC also expressed the costimulatory molecules CD80 and CD86 as determined with flow cytometry, the reverse transcription-polymerase chain reaction for RNA, and immunohistochemistry, and T-cell proliferation could be blocked by treating NEC and AEC with anti-CD80 and anti-CD86 antibodies. Our findings suggest that respiratory epithelial cells may have a role in local Ag presentation.
Am J Respir Cell Mol Biol 1999 Sep
PMID:Antigen trafficking and accessory cell function in respiratory epithelial cells. 1046 Jul 54

The aim of this study was to identify genes involved in human placentation. To do this, differential gene expression was assessed in the decidua (placental bed) from pre-eclamptic and normotensive pregnancies using the polymerase chain reaction (PCR)-based subtractive technique of representational difference analysis. A novel aspartyl protease (cathepsin D-like) cDNA sequence was isolated by virtue of its over-expression in the pre-eclamptic decidual sample tested. It was designated DAP-1 (for Decidual Aspartyl Protease 1). Using DAP-1 primer sequences a second cDNA (DAP-2) was subsequently isolated from decidual RNA by reverse transcription (RT)-PCR and found to be identical to DAP-1 apart from 80 additional and consecutive base pairs in the N-terminal coding region. In DAP-2, a stop codon within the unique 80 bp sequence was predicted to terminate translation immediately before the consensus active site residues. While Southern blotting was used to show that there are two loci with homology to DAP-1 in the human genome, it is postulated that alternative pre-mRNA splicing of the 80 bp exon is involved in the regulated expression of active (DAP-1) and inactive (DAP-2) forms of this novel protease; a mechanism similar to that involved in the regulated expression of Caspase-2, a protease involved in apoptosis. In other systems the regulation of alternative splicing is indicated by tissue specificity and developmental stage specificity of the various spliced products. In this context it was demonstrated that whereas DAP-1 was the major transcript expressed in decidua, the pattern was reversed in the adjacent placental tissue. It is proposed that tissue and developmental stage-specific expression of the DAP protease are important for the normal development and function of the uteroplacental tissues and that dysregulation of the control of DAP gene splicing may play a role in abnormal placentation, like that seen in pre-eclampsia.
Mol Hum Reprod 1999 Oct
PMID:Alternative forms of a novel aspartyl protease gene are differentially expressed in human gestational tissues. 1050 28

Non-denatured human placental cytosol fractions displaced tracer binding in parallel with gonadotrophin-releasing hormone (GnRH) isoform and agonist peptides in GnRH-specific radioimmunoassays and radioreceptor assays. However, placental immuno- and receptor binding-GnRH-like activity was highly correlated with inactivation of GnRH tracers, suggesting that placental GnRH-like factors may be an artefact of ligand degradation during assay. The properties and inhibitor sensitivities of the major (125)I-labelled GnRH-degrading enzymes of term placental cytosol were studied using a dextran-coated charcoal (DCC) adsorption assay as a rapid screen for GnRH tracer inactivation. Three different activities were demonstrable: (i) a cathepsin D-like enzyme (M(r) 55 kDa), active against all radiolabelled GnRH isoforms and agonists tested, optimal at acid pH, and inhibited specifically by pepstatin; (ii) a metallo-thiol endopeptidase activity (M(r) 70 kDa) optimal at alkaline pH (7-9) which degraded GnRH isoforms to a greater extent than GnRH analogues, inhibited dose-dependently by low concentrations of thiol reagents (N-ethylmaleimide, thimerosal), chelating agents (o-phenanthroline, EDTA), and by tosyl-phenylalanyl-chloromethyl ketone but not by other serine protease inhibitors; and (iii) a bacitracin-sensitive enzyme optimal at physiological pH. These observations permitted the development of a robust radioreceptor assay which minimized GnRH tracer degradation. Under these assay conditions, the GnRH-like radioreceptor assay activity of human placental cytosol fractions was markedly reduced.
Mol Hum Reprod 2000 Feb
PMID:Human placental gonadotrophin-releasing hormone-like factors: an artefact of human placental peptidases? 1065 53

The molecular machinery behind lysosome biogenesis and the maintenance of the perinuclear aggregate of late endocytic structures is not well understood. A likely candidate for being part of this machinery is the small GTPase Rab7, but it is unclear whether this protein is associated with lysosomes or plays any role in the regulation of the perinuclear lysosome compartment. Previously, Rab7 has mainly been implicated in transport from early to late endosomes. We have now used a new approach to analyze the role of Rab7: transient expression of Enhanced Green Fluorescent Protein (EGFP)-tagged Rab7 wt and mutant proteins in HeLa cells. EGFP-Rab7 wt was associated with late endocytic structures, mainly lysosomes, which aggregated and fused in the perinuclear region. The size of the individual lysosomes as well as the degree of perinuclear aggregation increased with the expression levels of EGFP-Rab7 wt and, more dramatically, the active EGFP-Rab7Q67L mutant. In contrast, upon expression of the dominant-negative mutants EGFP-Rab7T22N and EGFP-Rab7N125I, which localized mainly to the cytosol, the perinuclear lysosome aggregate disappeared and lysosomes, identified by colocalization of cathepsin D and lysosome-associated membrane protein-1, became dispersed throughout the cytoplasm, they were inaccessible to endocytosed molecules such as low-density lipoprotein, and their acidity was strongly reduced, as determined by decreased accumulation of the acidotropic probe LysoTracker Red. In contrast, early endosomes associated with Rab5 and the transferrin receptor, late endosomes enriched in the cation-independent mannose 6-phosphate receptor, and the trans-Golgi network, identified by its enrichment in TGN-38, were unchanged. These data demonstrate for the first time that Rab7, controlling aggregation and fusion of late endocytic structures/lysosomes, is essential for maintenance of the perinuclear lysosome compartment.
Mol Biol Cell 2000 Feb
PMID:Rab7: a key to lysosome biogenesis. 1067 7

Insulin-like growth factor-I (IGF-I), transforming growth factor alpha (TGFalpha) and epidermal growth factor (EGF) induced cathepsin D gene expression and reporter gene activity in MCF-7 human breast cancer cells transiently transfected with a construct (pCD1) containing a -2576 to -124 cathepsin D gene promoter insert. In contrast, IGF-I, but not TGFalpha or EGF, induced reporter gene activity in cells cotransfected with wild-type estrogen receptor (ER) expression plasmid and a construct (pCD2) containing estrogen-responsive downstream elements from -208 to -101. Promoter deletion and mutational analysis experiments identified four GC-rich sites and an imperfect palindromic estrogen responsive element required for IGF-I activation of the ER (ligand-independent). Subsequent studies with the mitogen-activated protein kinase (MAPK) inhibitor, PD98059, and a serine(118(-ER mutant confirmed the role of the MAPK pathway for IGF-I activation of the ER in MCF-7 cells. Thus, growth factor activation of ER can mediate transactivation vs ER/Sp1 binding to GC-rich sites and represents a novel pathway for ligand-independent ER action. The divergent pathways for IGF-I and TGFalpha/EGF activation of the ER observed in MCF-7 cells contrast with previous data indicating that pathways for growth factor activation of the ER are dependent on the gene and/or gene promoter and on cell context.
J Mol Endocrinol 2000 Apr
PMID:Transcriptional activation of cathepsin D gene expression by growth factors. 1075 20

17beta-Estradiol (E2) induces transforming growth factor alpha (TGFalpha) gene expression in MCF-7 cells and previous studies have identified a 53 bp (-252 to -200) sequence containing two imperfect estrogen responsive elements (EREs) that contribute to E2 responsiveness. Deletion analysis of the TGFalpha gene promoter in this study identified a second upstream region of the promoter (-623 to -549) that is also E2 responsive. This sequence contains three GC-rich sites and an imperfect ERE half-site, and the specific cis-elements and trans-acting factors were determined by promoter analysis in transient transfection experiments, gel mobility shift assays and in vitro DNA footprinting. The results are consistent with an estrogen receptor alpha (ERalpha)/Sp1 complex interacting with an Sp1(N)(30) ERE half-site ((1/2)) motif in which both ERalpha and Sp1 bind promoter DNA. The ER/Sp1-DNA complex is formed using nuclear extracts from MCF-7 cells but not with recombinant human ERalpha or Sp1 proteins, suggesting that other nuclear factor(s) are required for complex stabilization. The E2-responsive Sp1(N)(x)ERE(1/2) motif identified in the TGFalpha gene promoter has also been characterized in the cathepsin D and heat shock protein 27 gene promoters; however, in the latter two promoters the numbers of intervening nucleotides are 23 and 10 respectively.
J Mol Endocrinol 2000 Jun
PMID:Transcriptional activation of transforming growth factor alpha by estradiol: requirement for both a GC-rich site and an estrogen response element half-site. 1082 26

Maintenance of the appropriate pH in the intracellular vacuolar compartments is essential for normal cell function. Here, we report that CLN3 protein, which is associated with the juvenile form of neuronal ceroid lipofuscinosis (JNCL), participates in lysosomal pH homeostasis in human cells. We show that CLN3 protein increases lysosomal pH in cultured human embryonal kidney cells, whereas inhibition of CLN3 protein synthesis by antisense approach acidifies lysosomal compartments. These changes in lysosomal pH are sufficient to exert a significant biological effect and modify intracellular processing of amyloid-beta protein precursor and cathepsin D, model proteins whose metabolism is influenced by the pH of acidic organelles. Mutant CLN3 protein (R334C) that is associated with the classical JNCL phenotype was devoid of biological activities of wild-type CLN3 protein. These data suggest that the pathogenesis of juvenile neuronal ceroid lipofuscinosis is associated with altered acidification of lysosomal compartments. Furthermore, our study indicates that CLN3 protein affects metabolism of proteins essential for cell functions, such as amyloid-beta protein precursor, implicated in Alzheimer's disease pathogenesis.
Mol Genet Metab 2000 Jul
PMID:CLN3 protein regulates lysosomal pH and alters intracellular processing of Alzheimer's amyloid-beta protein precursor and cathepsin D in human cells. 1092 75

Neuronal ceroid lipofuscinoses (NCL) form a distinct group of storage diseases where the normal development of the central nervous system is interrupted and neurons of the neocortex begin to degenerate. Mutations in genes encoding three lysosomal enzymes are the causes for three early-onset forms of NCLs: palmitoyl-protein thioesterase 1 (PPT1) is deficient in human infantile NCL, tripeptidyl peptidase 1 (TTP1) in late-infantile NCL, and cathepsin D in congenital ovine NCL. We wanted to compare the developmental expression profiles of these enzymes in rat brain. In conclusion, the PPT1 expression pattern differed from the two other lysosomal enzymes implicated in NCL diseases, thus suggesting a distinctive role for PPT1 in brain development.
Mol Genet Metab
PMID:Developmental changes in the expression of neuronal ceroid lipofuscinoses-linked proteins. 1100 10

The cleavage of the amyloid precursor protein (APP) into amyloidogenic components (Abeta) is a central event in the pathogenesis of Alzheimer's disease (AD). FE65 is a protein that is involved in APP metabolism and may facilitate the production of Abeta. Recently, an intronic polymorphism of the gene encoding FE65 (FE65) was associated with altered risk for the development of sporadic AD. In our sample of 102 AD patients and 351 non-demented controls we did not replicate the association between FE65 and AD. Moreover, we observed no risk-modifying interaction and no linkage disequilibrium between FE65 and the gene encoding the acid protease cathepsin D (catD), which - like FE65 - is involved in APP metabolism and is also located on chromosome 11p15. We conclude that, whereas FE65 is implicated in AD pathology, the gene encoding FE65 does not appear to confer a substantial risk for AD.
Int J Mol Med 2000 Nov
PMID:No association between an intronic biallelic polymorphism of the FE65 gene and Alzheimer's disease. 1102 29

Proteolytic activities in alfalfa weevil (Hypera postica) larval midguts have been characterized. Effects of pH, thiol activators, low-molecular weight inhibitors, and proteinase inhibitors (PIs) on general substrate hydrolysis by midgut extracts were determined. Hemoglobinolytic activity was highest in the acidic to mildly acidic pH range, but was maximal at pH 3.5. Addition of thiol-activators dithiothreitol (DTT), 2-mercaptoethanol (2-ME), or L-cysteine had little effect on hemoglobin hydrolysis at pH 3.5, but enhanced azocaseinolytic activity two to three-fold at pH 5.0. The broad cysteine PI E-64 reduced azocaseinolytic activity by 64% or 42% at pH 5 in the presence or absence of 5 mM L-cysteine, respectively. Inhibition by diazomethyl ketones, Z-Phe-Phe-CHN(2) and Z-Phe-Ala-CHN(2), suggest that cathepsins L and B are present and comprise approximately 70% and 30% of the cysteine proteolytic activity, respectively. An aspartyl proteinase component was identified using pepstatin A, which inhibited 32% (pH 3.5, hemoglobin) and 50% (pH 5, azocasein) of total proteolytic activity. This activity was completely inhibited by an aspartyl proteinase inhibitor from potato (API), and is consistent with the action of a cathepsin D-like enzyme. Hence, genes encoding PIs with specificity toward cathepsins L, B and D could potentially be effective for control of alfalfa weevil using transgenic plants.
Insect Biochem Mol Biol 2000 Dec
PMID:Inhibition of cysteine and aspartyl proteinases in the alfalfa weevil midgut with biochemical and plant-derived proteinase inhibitors. 1104 64


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