RESUMO
It is possible that Denmark has a high proportion of patients with undiagnosed coeliac disease in the general population and in such risk groups as patients with autoimmune endocrinological and neurological disorders. An active diagnostic strategy, with screening of patients at risk is proposed. Several gliadin epitopes that might be pathogenetically important are described. Tissue transglutaminase is an autoantigen and a deamidating factor in vitro.
Assuntos
Doença Celíaca/diagnóstico , Doenças Autoimunes/diagnóstico , Doença Celíaca/genética , Doença Celíaca/imunologia , Dinamarca/epidemiologia , Epitopos/genética , Predisposição Genética para Doença , Gliadina/genética , Gliadina/imunologia , Humanos , Programas de Rastreamento , Fatores de RiscoRESUMO
It has been suggested that detergent-resistant membranes (DRMs), also known as lipid rafts, are involved in vectorial transport of proteins to the apical surface. In this report we use Madin-Darby canine kidney (MDCK) cells expressing the apically secreted C1-esterase inhibitor, the non-sorted antithrombin or chimeras of serpins to study the possible connection between DRM association and apical targeting of secretory proteins. We found newly synthesised C1-esterase inhibitor associated with DRMs in MDCK cells, whereas antithrombin was not. However, two chimeric proteins, secreted mainly from the apical membrane, do not associate with DRMs. Based on these observations we suggest that apical targeting and association with DRMs are two independent events for secretory serpins.
Assuntos
Microdomínios da Membrana/metabolismo , Serpinas/metabolismo , Animais , Linhagem Celular , Membrana Celular/metabolismo , Células Cultivadas , Centrifugação com Gradiente de Concentração , Colesterol/metabolismo , Colesterol/farmacologia , Detergentes/farmacologia , Cães , Vetores Genéticos , Concentração de Íons de Hidrogênio , Immunoblotting , Testes de Precipitina , Sacarose/farmacologia , TransfecçãoRESUMO
The three members of the serpin family, corticosteroid binding globulin, alpha1-antitrypsin, and C1 inhibitor are secreted apically from Madin-Darby canine kidney (MDCK) cells, whereas two homologous family members, antithrombin and plasminogen activator inhibitor-1, are secreted in a nonpolarized fashion. cDNAs coding for chimeras composed of complementary portions of an apically targeted serpin and a nonsorted serpin were generated, expressed in MDCK cells, and the ratio between apical and basolateral secretion was analyzed. These experiments identified an amino-terminal sequence of corticosteroid binding globulin (residues 1-19) that is sufficient to direct a chimera with antithrombin mainly to the apical side. A deletion/mutagenesis analysis showed that no individual amino acid is absolutely required for the apical targeting ability of amino acids 1-30 of corticosteroid binding globulin. The corresponding amino-terminal sequences of alpha1-antitrypsin and C1 inhibitor were also sufficient to confer apical sorting. Based on our results we suggest that the apical targeting ability is encoded in the conformation of the protein.
Assuntos
Antitrombinas/química , Antitrombinas/metabolismo , Sequência de Aminoácidos , Animais , DNA/metabolismo , DNA Complementar/metabolismo , Cães , Deleção de Genes , Dados de Sequência Molecular , Mutação , Testes de Precipitina , Conformação Proteica , Estrutura Terciária de Proteína , Proteínas Recombinantes de Fusão/metabolismo , Homologia de Sequência de AminoácidosRESUMO
Truncated human coronavirus HCoV-229E spike glycoproteins containing amino acids 407 to 547 bound to purified, soluble virus receptor, human aminopeptidase N (hAPN). Soluble hAPN neutralized the infectivity of HCoV-229E virions at 37 degrees C, but not 4 degrees C. Binding of hAPN may therefore trigger conformational changes in the viral spike protein at 37 degrees C that facilitate virus entry.