| THE GPI ANCHOR OF CELL-SURFACE PROTEINS IS SYNTHESIZED ON THE CYTOPLASMIC FACE OF THE ENDOPLASMIC-RETICULUM |
|
|
| Author(s): VIDUGIRIENE J, MENON AK |
| Source: JOURNAL OF CELL BIOLOGY Volume: 127 Issue: 2 Pages: 333-341 Published: OCT 1994 |
| Times Cited: 87 References: 48 |
| Abstract: Glycosylphosphatidylinositol (GPI) membrane protein anchors are synthesized from sugar nucleotides and phospholipids in the ER and transferred to newly synthesized proteins destined for the cell surface. The topology of GPI synthesis in the ER was investigated using sealed trypanosome microsomes and the membrane-impermeant probes phosphatidylinositol-specific phospholipase C, Con A, and proteinase K. All the GPI biosynthetic intermediates examined were found to be located on the external face of the microsomal vesicles suggesting that the principal steps of GPI assembly occur in the cytoplasmic leaflet of the ER. Protease protection experiments showed that newly GPI-modified trypanosome variant surface glycoprotein was primarily oriented towards the ER lumen, consistent with eventual expression at the cell surface. The unusual topographical arrangement of the GPI assembly pathway suggests that a biosynthetic intermediate, possibly the phosphoethanolamine-containing anchor precursor, must be translocated across the ER membrane bilayer in the process of constructing a GPI anchor. |
| Document Type: Article |
| Language: English |
Addresses:
1. UNIV WISCONSIN, DEPT BIOCHEM, MADISON, WI 53706 USA |
| Publisher: ROCKEFELLER UNIV PRESS, 1114 FIRST AVE, 4TH FL, NEW YORK, NY 10021 |
| Subject Category: Cell Biology |
| IDS Number: PM416 |
| ISSN: 0021-9525 |