Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Mol Biol Cell. 2003 Oct;14(10):4285-95. Epub 2003 Jun 13.

PIG-W is critical for inositol acylation but not for flipping of glycosylphosphatidylinositol-anchor.

Author information

  • 1Department of Immunoregulation, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan.

Abstract

Many cell surface proteins are anchored to a membrane via a glycosylphosphatidylinositol (GPI), which is attached to the C termini in the endoplasmic reticulum. The inositol ring of phosphatidylinositol is acylated during biosynthesis of GPI. In mammalian cells, the acyl chain is added to glucosaminyl phosphatidylinositol at the third step in the GPI biosynthetic pathway and then is usually removed soon after the attachment of GPIs to proteins. The mechanisms and roles of the inositol acylation and deacylation have not been well clarified. Herein, we report derivation of human and Chinese hamster mutant cells defective in inositol acylation and the gene responsible, PIG-W. The surface expressions of GPI-anchored proteins on these mutant cells were greatly diminished, indicating the critical role of inositol acylation. PIG-W encodes a 504-amino acid protein expressed in the endoplasmic reticulum. PIG-W is most likely inositol acyltransferase itself because the tagged PIG-W affinity purified from transfected human cells had inositol acyltransferase activity and because both mutant cells were complemented with PIG-W homologs of Saccharomyces cerevisiae and Schizosaccharomyces pombe. The inositol acylation is not essential for the subsequent mannosylation, indicating that glucosaminyl phosphatidylinositol can flip from the cytoplasmic side to the luminal side of the endoplasmic reticulum.

PMID:
14517336
[PubMed - indexed for MEDLINE]
PMCID:
PMC207019
Free PMC Article

Images from this publication.See all images (9)Free text

Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk