Svp1p defines a family of phosphatidylinositol 3,5-bisphosphate effectors

• DOI: 10.1038/sj.emboj.7600203
• Publication Date: 2004-04-22T08:51:54Z
• Authors: Stephen K Dove; Robert C Piper; Robert K McEwen; Jong W Yu; Megan C King; David C Hughes; Jan Thuring; Andrew B Holmes; Frank T Cooke; Robert H Michell; Peter J Parker; Mark A Lemmon
• Keywords: 0301 basic medicine; 570; Protein Folding; Saccharomyces cerevisiae Proteins; Rhinovirus; Genetic Vectors; Green Fluorescent Proteins; Molecular Sequence Data; Autophagy-Related Proteins; 612; Endosomes; Saccharomyces cerevisiae; 12. Responsible consumption; 03 medical and health sciences; Phosphatidylinositol Phosphates; Escherichia coli; Amino Acid Sequence; Cloning, Molecular; Base Sequence; Membrane Proteins; Phosphotransferases (Alcohol Group Acceptor); Protein Transport; Gene Components; Plasmids; Protein Binding

Phosphatidylinositol 3,5-bisphosphate (PtdIns(3,5)P2), made by Fab1p, is essential for vesicle recycling from vacuole/lysosomal compartments and for protein sorting into multivesicular bodies. To isolate PtdIns(3,5)P2 effectors, we identified Saccharomyces cerevisiae mutants that display fab1delta-like vacuole enlargement, one of which lacked the SVP1/YFR021w/ATG18 gene. Expressed Svp1p displays PtdIns(3,5)P2 binding of exquisite specificity, GFP-Svp1p localises to the vacuole membrane in a Fab1p-dependent manner, and svp1delta cells fail to recycle a marker protein from the vacuole to the Golgi. Cells lacking Svp1p accumulate abnormally large amounts of PtdIns(3,5)P2. These observations identify Svp1p as a PtdIns(3,5)P2 effector required for PtdIns(3,5)P2-dependent membrane recycling from the vacuole. Other Svp1p-related proteins, including human and Drosophila homologues, bind PtdIns(3,5)P2 similarly. Svp1p and related proteins almost certainly fold as beta-propellers, and the PtdIns(3,5)P2-binding site is on the beta-propeller. It is likely that many of the Svp1p-related proteins that are ubiquitous throughout the eukaryotes are PtdIns(3,5)P2 effectors. Svp1p is not involved in the contributions of FAB1/PtdIns(3,5)P2 to MVB sorting or to vacuole acidification and so additional PtdIns(3,5)P2 effectors must exist.