Many eukaryotic cell surface proteins are anchored to the plasma membrane via glycosylphosphatidylinositol (GPI). The GPI transamidase mediates GPI anchoring in the endoplasmic reticulum, by replacing a protein's C-terminal GPI attachment signal peptide with a pre-assembled GPI. During this transamidation reaction, the GPI transamidase forms a carbonyl intermediate with a substrate protein. It was known that the GPI transamidase is a complex containing GAA1 and GPI8. Here, we report two new components of this enzyme: PIG-S and PIG-T. To determine roles for PIG-S and PIG-T, we disrupted these genes in mouse F9 cells by homologous recombination. PIG-S and PIG-T knockout cells were defective in transfer of GPI to proteins, particularly in formation of the carbonyl intermediates. We also demonstrate that PIG-S and PIG-T form a protein complex with GAA1 and GPI8, and that PIG-T maintains the complex by stabilizing the expression of GAA1 and GPI8. Saccharomyces cerevisiae Gpi16p (YHR188C) and Gpi17p (YDR434W) are orthologues of PIG-T and PIG-S, respectively.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|