Fab1p PtdIns(3)P 5-Kinase Function Essential for Protein Sorting in the Multivesicular Body

摘要: Abstract Sorting of signal-transducing cell surface receptors within multivesicular bodies (MVBs) is required for their rapid down-regulation and degradation lysosomes. Yeast mutants defective in late stages transport to the vacuole/lysosome accumulate MVBs. We demonstrate that membrane glycoprotein carboxypeptidase S G protein–coupled receptor Ste2p are targeted into vacuole lumen, this process requires a subset VPS gene products essential normal endosome function. The PtdIns(3)P 5-kinase activity Fab1p, which converts product Vps34p PtdIns 3-kinase PtdIns(3,5)P 2 , also cargo-selective sorting lumen. These findings role phosphoinositide signaling at distinct vacuolar/lysosomal protein couple synthesis regulation MVB sorting.