Interaction of Wnt-1 proteins with the binding protein BiP.
AUTOR(ES)
Kitajewski, J
RESUMO
The mouse Wnt-1 gene, a target for insertional activation in mouse mammary tumor virus-induced mammary tumors, encodes poorly secreted, cysteine-rich glycoproteins required for proper central nervous system development. We have been analyzing the biosynthesis of Wnt-1 proteins in several cell lines that express Wnt-1 cDNA from heterologous promoters. A protein of 78 kDa was found to be associated with the intracellular forms of Wnt-1 proteins in mammalian and avian cells by using multiple antisera against Wnt-1 proteins. We have identified p78 as the binding protein BiP with anti-BiP antisera and by its release from Wnt-1 immunoprecipitates upon incubation with MgCl2 and ATP. Experiments with a Wnt-1 mutant that lacks the sequence encoding the signal peptide indicates that Wnt-1 proteins must enter the secretory pathway in order to interact with BiP. We demonstrate that Wnt-1 proteins are associated with BiP in cells in which active Wnt-1 proteins are produced, such as a cultured mammary epithelial cell line and Wnt-1 transgenic mouse mammary tumor cells. The association of Wnt-1 proteins with BiP may be a factor in determining the efficiency of secretion of Wnt-1 gene products.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=364299Documentos Relacionados
- Similarity of nucleotide interactions of BiP and GTP-binding proteins.
- Interconversion of three differentially modified and assembled forms of BiP.
- Binding protein BiP is required for translocation of secretory proteins into the endoplasmic reticulum in Saccharomyces cerevisiae.
- Interaction of BiP with newly synthesized immunoglobulin light chain molecules: cycles of sequential binding and release.
- Inhibition of endoplasmic reticulum (ER)-to-Golgi transport induces relocalization of binding protein (BiP) within the ER to form the BiP bodies.