Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 2 de 2
Filtrar
Mais filtros

Base de dados
Ano de publicação
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
J Cell Biochem ; 113(3): 934-45, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22371973

RESUMO

Zonula occludens protein 1 (ZO-1) is a ubiquitous scaffolding protein, but it is unknown why it functions in very different cellular contacts. We hypothesized that a specific segment, the unique hinge region, can be bound by very different regulatory proteins. Using surface plasmon resonance spectroscopy and binding assays to peptide libraries, we show, for the first time, that the hinge region directly interacts with disparate signal elements such as G-proteins alpha 12 and alpha i2, the regulator of G-protein signaling 5, multifunctional signaling protein ahnak1, and L-type Ca2+-channel beta-2-subunit. The novel binding proteins specifically bound to a coiled coil-helix predicted in the hinge region of ZO-. The interactions were modulated by phosphorylation in the hinge helix. Activation of the G-proteins influenced their association to ZO-1. In colon cells, G alpha i2 and ZO-1 were associated, as shown by coimmunoprecipitation. After cotransfection in kidney cells, G alpha i2 barely colocalized with ZO-1; the colocalization coefficient was significantly increased when epinephrine activated G-protein signaling. In conclusion, proteins with different regulatory potential adhere to and influence cellular functions of ZO-proteins, and the interactions can be modulated via its hinge region and/or the binding proteins.


Assuntos
Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/metabolismo , Fosfoproteínas/metabolismo , Células CACO-2 , Membrana Celular/química , Células Epiteliais/química , Células Epiteliais/metabolismo , Subunidade alfa Gi2 de Proteína de Ligação ao GTP/metabolismo , Células HEK293 , Humanos , Proteínas de Membrana/análise , Proteínas de Membrana/química , Fosfoproteínas/análise , Fosfoproteínas/química , Proteínas RGS/metabolismo , Proteína da Zônula de Oclusão-1
2.
Ann N Y Acad Sci ; 1165: 19-27, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19538283

RESUMO

The transmembrane tight junction protein occludin is sensitive to oxidative stress. Occludin oligomerizes; however, its function in the tight junction is unknown. The cytosolic C-terminal tail contains a coiled coil-domain and forms dimers contributing to the oligomerization. The regulation of the oligomerization remains unclear. As the domain area contains sulfhydryl residues, we tested the hypothesis that the dimerization of the coiled coil-domain depends on these residues. We showed that the dimerization is modulated by the thiol concentration in the low-millimolar range, which is relevant both for physiological and pathophysiological conditions. Masking the sulfhydryl residues in the fragment by covalent binding of 4-vinyl pyridine prevented the dimerization but did not affect its helical structure and cylindric shape. The data demonstrate, for the first time, that disulfide bridge formation of murine cystein 408 is involved in the dimerization. This process is redox-sensitive but the secondary structure of the domain is not. It is concluded that the dimerization of occludin may play a regulatory role in the tight junction assembly under physiological and pathological conditions.


Assuntos
Proteínas de Membrana/química , Animais , Sítios de Ligação , Cisteína/genética , Cisteína/metabolismo , Espectrometria de Massas , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Ocludina , Oxirredução , Multimerização Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Junções Íntimas/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA