SUMMARY PARAGRAPH for BST1
Bst1p is a glycosylphosphatidylinositol (GPI) inositol deacylase that mediates inositol deacylation of GPI-anchored proteins, which may be required for their efficient incorporation into COPII transport vesicles through association with cargo receptors (3). An integral membrane protein that resides predominantly in the endoplasmic reticulum (ER), Bst1p negatively regulates COPII vesicle formation, preventing the production of vesicles with defective or missing subunits (1). Bst1p is also required for proper discrimination between resident ER proteins and Golgi-bound cargo molecules (2), and is required for the transport of misfolded proteins to the Golgi, though dispensable for the transport of many normal cargo proteins (1). Bst1p also plays a role in the retrieval to the ER of proteins transported to the Golgi apparatus via COPII-coated vesicles. Bst1p thus represents a novel class of ER proteins that link the regulation of vesicle coat assembly to cargo sorting (2). Null mutations in BST1 suppress mutations in the essential COPII gene SEC13, which is important for the formation of ER to Golgi transport vesicles (2).
Last updated: 2004-11-02