Phox domain interaction with PtdIns(3)P targets the Vam7 t-SNARE to vacuole membranes.
Specific recognition of phosphoinositides is crucial for protein sorting and membrane trafficking. Protein transport to the yeast vacuole depends on the Vam7 t-SNARE and its phox homology (PX) domain. Here, we show that the PX domain of Vam7 targets to vacuoles in vivo in a manner dependent on phosphatidylinositol 3-phosphate generation. A novel phosphatidylinositol-3-phosphate-binding motif and an exposed loop that interacts with the lipid bilayer are identified by nuclear magnetic resonance spectroscopy. Conservation of key structural and binding site residues across the diverse PX family indicates a shared fold and phosphoinositide recognition function.
Cheever
M L
ML
Molecular Biology Program, University of Colorado Health Sciences Center, 4200 East Ninth Avenue, Denver, Colorado 80262, USA.
Sato
T K
TK
de Beer
T
T
Kutateladze
T G
TG
Emr
S D
SD
Overduin
M
M
D000595:Amino Acid Sequence; D001665:Binding Sites; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism*; D007425:Intracellular Membranes / Q000737:chemistry / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D008567:Membranes, Artificial; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D019906:Nuclear Magnetic Resonance, Biomolecular; D018129:Phosphatidylinositol Phosphates / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000502:physiology; D050767:Qc-SNARE Proteins; D050600:SNARE Proteins; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D050825:Synaptosomal-Associated Protein 25; D014617:Vacuoles / Q000502:physiology / Q000648:ultrastructure; D033921:Vesicular Transport Proteins
D005656:Fungal Proteins; D008565:Membrane Proteins; D008567:Membranes, Artificial; D009419:Nerve Tissue Proteins; D018129:Phosphatidylinositol Phosphates; D050767:Qc-SNARE Proteins; D050600:SNARE Proteins; D029701:Saccharomyces cerevisiae Proteins; D050825:Synaptosomal-Associated Protein 25; C494205:VAM7 protein, S cerevisiae; D033921:Vesicular Transport Proteins; C055525:phosphatidylinositol 3-phosphate