The Riezman group reported yeast GAA1 (for GPI Anchor Attachment 1), the first component of GPI transamidase to be identified.
The Conzelmann group identified yeast GPI8 as a catalytic component of GPI transamidase.
Ohishi isolated the GPI transamidase complex and identified two more components.
Ohishi cloned the PIGT gene based on the N-terminal sequence of the other component, which he found in the isolated GPI transamidase.
The other four GPI transamidase components formed a complex in the absence of PIG-U, suggesting that PIG-U is positioned at the periphery of the enzyme complex.
In the ER of the PIGV-defective cells, the C-terminal GPI attachment signal peptide of a nascent protein, such as alkaline phosphatase, is cleaved by GPI transamidase and the major part of the protein is either secreted without GPI-anchoring or degraded by ER-associated degradation.
The affected individuals had hypophosphatasia, rather than hyperphosphatasia, (79) being consistent with our proposal that secretion of alkaline phosphatase is dependent upon GPI transamidase.
2000) Gaa1p and gpi8p are components of a glycosylphosphatidylinositol (GPI) transamidase that mediates attachment of GPI to proteins.
2002) Structural requirements for the recruitment of gaa1 into a functional glycosylphosphatidylinositol transamidase complex.
1997) The affected gene underlying the class K glycosylphosphatidylinositol (GPI) surface protein defect codes for the GPI transamidase.