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PIG‐S and PIG‐T, essential for GPI anchor attachment to proteins, form a complex with GAA1 and GPI8
Author(s) -
Ohishi Kazuhito,
Inoue Norimitsu,
Kinoshita Taroh
Publication year - 2001
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/20.15.4088
Subject(s) - biology , microbiology and biotechnology
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.