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The localization of bullous pemphigoid antigen 180 (BP180) in hemidesmosomes is mediated by its cytoplasmic domain and seems to be regulated by the beta4 integrin subunit.

ABSTRACT: Bullous pemphigoid antigen 180 (BP180) is a component of hemidesmosomes, i.e., cell-substrate adhesion complexes. To determine the function of specific sequences of BP180 to its incorporation in hemidesmosomes, we have transfected 804G cells with cDNA-constructs encoding wild-type and deletion mutant forms of human BP180. The results show that the cytoplasmic domain of BP180 contains sufficient information for the recruitment of the protein into hemidesmosomes because removal of the extracellular and transmembrane domains does not abolish targeting. Expression of chimeric proteins, which consist of the membrane targeting sequence of K-Ras fused to the cytoplasmic domain of BP180 with increasing internal deletions or lacking the NH2 terminus, indicates that the localization of BP180 in hemidesmosomes is mediated by a segment that spans 265 amino acids. This segment comprises two important regions located within the central part and at the NH2 terminus of the cytoplasmic domain of BP180. To investigate the effect of the alpha6beta4 integrin on the subcellular distribution of BP180, we have transfected COS-7 cells, which lack alpha6beta4 and BP180, with cDNAs for BP180 as well as for human alpha6A and beta4. We provide evidence that a mutant form of BP180 lacking the collagenous extracellular domain as well as a chimeric protein, which contains the entire cytoplasmic domain of BP180, are colocalized with alpha6beta4. In contrast, when cells were transfected with cDNAs for alpha6A and mutant forms of beta4, either lacking the cytoplasmic COOH-terminal half or carrying phenylalanine substitutions in the tyrosine activation motif of the cytoplasmic domain, the recombinant BP180 molecules were mostly not colocalized with alpha6beta4, but remained diffusely distributed at the cell surface. Moreover, in cells transfected with cDNAs for alpha6A and a beta4/beta1 chimera, in which the cytoplasmic domain of beta4 was replaced by that of the beta1 integrin subunit, BP180 was not colocalized with the alpha6beta4/beta1 chimera in focal adhesions, but remained again diffusely distributed. These results indicate that sequences within the cytoplasmic domain of beta4 determine the subcellular distribution of BP180.

SUBMITTER: Borradori L

PROVIDER: S-EPMC2132520 | biostudies-literature | 1997 Mar

REPOSITORIES: biostudies-literature

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The localization of bullous pemphigoid antigen 180 (BP180) in hemidesmosomes is mediated by its cytoplasmic domain and seems to be regulated by the beta4 integrin subunit.

Borradori L L Koch P J PJ Niessen C M CM Erkeland S S van Leusden M R MR Sonnenberg A A

The Journal of cell biology 19970301 6

Bullous pemphigoid antigen 180 (BP180) is a component of hemidesmosomes, i.e., cell-substrate adhesion complexes. To determine the function of specific sequences of BP180 to its incorporation in hemidesmosomes, we have transfected 804G cells with cDNA-constructs encoding wild-type and deletion mutant forms of human BP180. The results show that the cytoplasmic domain of BP180 contains sufficient information for the recruitment of the protein into hemidesmosomes because removal of the extracellula ...[more]

PMID: 9087447

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Project description:Importance:Enzyme-linked immunosorbent assay (ELISA) and/or chemiluminescent enzyme immunoassay (CLEIA) for BP180 noncollagenous 16A (NC16A) extracellular domain is a sensitive diagnostic tool for bullous pemphigoid (BP). However, some patients with BP have negative results for these assays. Objective:To elucidate the clinical and immunological features of patients with BP without antibodies that react to BP180 NC16A. Design, Setting, and Participants:This retrospective case series study included 152 patients who were diagnosed with BP and followed up at the Kurume University Hospital in Japan from 2007 to 2016. The diagnosis was made using clinical, histological, and immunological findings. Main Outcomes and Measures:Clinical and immunological features of patients with BP who had negative results for BP180 NC16A using ELISA and/or CLEIA. Results:Of the 152 patients, 69 (45.4%) were men and 83 (54.6%) were women. The mean (SD) age of participants was 75.2 (14.4) years. Of the 152 patients with BP, 14 (9.2%) had negative results for BP180 NC16A on ELISA and/or CLEIA; most of these patients exhibited no erythema and had relatively mild phenotypes. Two (14%) of the 14 patients had positive results for intact BP180 in epidermal extracts, 10 (71%) had positive results for a 120-kD fragment of BP180 (LAD-1) and 3 (21%) had positive results for BP180 C-terminal domain. Seven (50%) patients tested positive in BP230 ELISA. Five (36%) patients did not require oral prednisolone treatment, whereas the others required a dose of prednisolone at less than 30 mg per day. Three (21%) patients were administered a dipeptidyl peptidase-4 inhibitor (DPP4i) before disease onset. This ratio was not significantly higher than that in patients with BP who tested positive for BP180 NC16A ELISA and/or CLEIA (19 [14%] of 138 patients). Our follow-up study (mean [SD], 31.9 [33.2] weeks; range, 0-108 weeks) revealed that patients with BP tested negative for BP180 NC16A ELISA and/or CLEIA during the later stages of the disease. Conclusions and Relevance:This study indicates that patients with BP negative for BP180 NC16A ELISA and/or CLEIA had milder phenotypes, fewer erythemas, and required less extensive treatments.

Project description:BackgroundBullous pemphigoid (BP) is the most common autoimmune blistering disease in the West. Oral steroids are the standard treatment.This is an update of the review published in 2005.ObjectivesTo assess treatments for bullous pemphigoid.Search strategyIn August 2010 we updated our searches of the Cochrane Skin Group Specialised Register, the Cochrane Central Register of Controlled Trials (Clinical Trials), MEDLINE, EMBASE, and the Ongoing Trials registers.Selection criteriaRandomised controlled trials of treatments for participants with immunofluorescence-confirmed bullous pemphigoid.Data collection and analysisAt least two authors evaluated the studies for the inclusion criteria, and extracted data independently.Main resultsWe included 10 randomised controlled trials (with a total of 1049 participants) of moderate to high risk of bias. All studies involved different comparisons, none had a placebo group. In 1 trial plasma exchange plus prednisone gave significantly better disease control at 1 month (0.3 mg/kg: RR 18.78, 95% CI 1.20 to 293.70) than prednisone alone (1.0 mg/kg: RR 1.79, 95% CI 1.11 to 2.90), while another trial showed no difference in disease control at 6 months.No differences in disease control were seen for different doses or formulations of prednisolone (one trial each), for azathioprine plus prednisone compared with prednisone alone (one trial), for prednisolone plus azathioprine compared with prednisolone plus plasma exchange (one trial), for prednisolone plus mycophenolate mofetil or plus azathioprine (one trial), for tetracycline plus nicotinamide compared with prednisolone (one trial). Chinese traditional medicine plus prednisone was not effective in one trial.There were no significant differences in healing in a comparison of a standard regimen of topical steroids (clobetasol) with a milder regimen (RR 1.00, 95% 0.97 to 1.03) in one trial. In another trial, clobetasol showed significantly more disease control than oral prednisolone in people with extensive and moderate disease (RR 1.09, 95% CI 1.02 to 1.17), with significantly reduced mortality and adverse events (RR 1.06, 95% CI 1.00 to 1.12).Authors' conclusionsVery potent topical steroids are effective and safe treatments for BP, but their use in extensive disease may be limited by side-effects and practical factors. Milder regimens (using lower doses of steroids) are safe and effective in moderate BP. Starting doses of prednisolone greater than 0.75 mg/kg/day do not give additional benefit, lower doses may be adequate to control disease and reduce the incidence and severity of adverse reactions. The effectiveness of adding plasma exchange, azathioprine or mycophenolate mofetil to corticosteroids, and combination treatment with tetracycline and nicotinamide needs further investigation.

Project description:Bullous pemphigoid (BP) is a rare autoimmune skin blistering disease, characterized by the presence of autoantibodies against hemidesmosomal autoantigens. Cytokine expression is altered in BP patients, and several of these differently expressed cytokines, including IL-1α, IL-1β, IL-8, and TNF-α, contribute to disease pathogenesis. Since genetic polymorphisms in the genes of these cytokines might be implicated in susceptibility to BP disease, we aimed at testing this implication in susceptibility to BP in an Iranian cohort. Blood samples were collected from the subjects and genomic DNA was extracted. To detect the single nucleotide polymorphisms (SNPs), IL-1α (rs1800587), IL-1β (rs1143627, rs16944, rs1143634), IL-8 (rs4073), and TNF-α (rs1799964, rs1800630, rs1799724, and rs361525) genes were genotyped in BP patients and healthy controls as well as IL-8 (rs4073) in pemphigus vulgaris (PV) patients. Quantitative gene expression was evaluated by RT-PCR analysis. A significant difference was observed in the distribution of genotypes or alleles of IL-8 SNP between the BP patients and controls. The A-allele of IL-8 SNP is significantly more prevalent in the control individuals compared to the BP patient. To further validate this observation, we included PV patients as an additional control. Again, the A-allele of IL-8 SNP is significantly more prevalent in the PV compared to the BP patients. While we observed a trend toward significant differences regarding alleles of TNF-α rs1799724 as well as alleles of TNF-α rs1799964, this difference was, however, not evident after correction for multiple analysis. There was no significant difference in all other studied SNPs. In contrast to IL-1α, IL-1β, and TNF-α, IL-8 gene expression levels were significantly higher in the patients than that of controls. The minor allele in IL-8 SNP might play a protective role in susceptibility to BP in Iranian patients. Although higher expression levels of IL-8 gene was found in the patients compared with healthy controls, these levels, however, suggest no association with the examined polymorphism. Moreover, further investigation revealed an elevation in gene expression between wild and polymorphic genotypes of IL-1α rs1800587 and TNF-α rs361525 in the patient group and these SNPs are therefore associated with altering the levels of gene expression.

Dataset Information

The localization of bullous pemphigoid antigen 180 (BP180) in hemidesmosomes is mediated by its cytoplasmic domain and seems to be regulated by the beta4 integrin subunit.

Publications

The localization of bullous pemphigoid antigen 180 (BP180) in hemidesmosomes is mediated by its cytoplasmic domain and seems to be regulated by the beta4 integrin subunit.

Similar Datasets

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