At the early endosome membrane, the PAS complex, consisting of mouse FYVE finger-containing phosphoinositide kinase (Pikfyve), yeast VAC14 homologue (VAC14), and polyphosphoinositide phosphatase aka SAC3 (FIG4), binds to the membrane via Pikfyve's FYVE finger (Sbrissa et al. 2002, Cao et al. 2007). The Pikfyve kinase component phosphorylates phosphatidylinositol 3-phosphate (PI3P) to phosphatidylinositol 3,5-bisphosphate PI(3,5)P2 (Sbrissa et al. 1999). The PAS complex is present in the cytosol and is recruited to the membrane (Sbrissa et al. 2007).