Vectorial apical delivery and slow endocytosis of a glycolipid-anchored fusion protein in transfected MDCK cells.
AUTOR(ES)
Lisanti, M P
RESUMO
To characterize the mechanisms that determine the apical polarity of proteins anchored by glycosylphosphatidylinositol (GPI), we studied the targeting of a GPI-anchored form of a herpes simplex glycoprotein, gD-1, in transfected MDCK cells. Using a biotin-based targeting assay, we found that GPI-anchored gD-1 was sorted intracellularly and delivered directly to the apical surface. Endocytosis of GPI-anchored gD-1 occurred slowly and preferentially from the apical domain, while transcytosis of the basolateral fraction did not occur at a significant rate (incompatible with being a precursor to the apical pool). Prevention of tight junction formation by incubation in medium with micromolar Ca2+ resulted in expression of GPI-anchored gD-1 on the free surface, but not on the attached surface of the cell. Our results indicate that the apical polarity of a GPI-anchored protein is generated by vectorial delivery to the apical membrane, where its distribution is maintained by slow endocytosis and by a retention system not necessarily involving the tight junction.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=54758Documentos Relacionados
- Oligomerization of glycolipid-anchored and soluble forms of the vesicular stomatitis virus glycoprotein.
- Construction, purification, and functional incorporation on tumor cells of glycolipid-anchored human B7-1 (CD80).
- Human immunodeficiency virus infection is efficiently mediated by a glycolipid-anchored form of CD4.
- Complex alternative splicing of acetylcholinesterase transcripts in Torpedo electric organ; primary structure of the precursor of the glycolipid-anchored dimeric form.
- Anchoring and degradation of glycolipid-anchored membrane proteins by L929 versus by LM-TK- mouse fibroblasts: implications for anchor biosynthesis.
