A heterotrimeric GProtein, G«i-3 , on Golgi membranes regulates the secretion of a heparan sulfate proteoglycan in LLC-PKI epithelial cells
A heterotrimeric Gai subunit, «i- 3 , is localized on Golgi membranes in LLC-PKI and NRK epithelial cells where it colocalizes with mannosidase II by immunofluorescence . The M-3 was found to be localized on the cytoplasmic face of Golgi cisternae and it was distributed across the whole Golgi stack....
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 1991 |
| País: | Brasil |
| Institución: | Universidade Federal do Rio Grande do Norte (UFRN) |
| Repositorio: | Repositório Institucional da UFRN |
| Idioma: | inglés |
| OAI Identifier: | oai:repositorio.ufrn.br:123456789/54389 |
| Acceso en línea: | https://repositorio.ufrn.br/handle/123456789/54389 https://doi.org/10.1083/jcb.114.6.1113 |
| Access Level: | acceso abierto |
| Palabra clave: | heterotrimeric G protein golgi |
| Sumario: | A heterotrimeric Gai subunit, «i- 3 , is localized on Golgi membranes in LLC-PKI and NRK epithelial cells where it colocalizes with mannosidase II by immunofluorescence . The M-3 was found to be localized on the cytoplasmic face of Golgi cisternae and it was distributed across the whole Golgi stack. The a;_3 subunit is found on isolated rat liver Golgi membranes by Western blotting and Gai -3 on the Golgi apparatus is ADP ribosylated by pertussis toxin. LLCPKI cells were stably transfected with GO;-3 on an MT1, inducible promoter in order to overexpress ai-3 on Golgi membranes. The intracellular processing and constitutive secretion of the basement membrane heparan sulfate proteoglycan (HSPG) was measured in LLC-PK, cells. Overexpression of ai-3 on Golgi membranes in transfected cells retarded the secretion of HSPG and accumulated precursors in the medial-trans-Golgi . This effect was reversed by treatment of cells with pertussis toxin which results in ADP-ribosylation and functional uncoupling of Gai-3 on Golgi membranes. These results provide evidence for a novel role for the pertussis toxin sensitive Gai-3 protein in Golgi trafficking of a constitutively secreted protein in epithelial cells |
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