PI3P is phosphorylated to PI(3,5)P2 by PIKFYVE at the early endosome membrane

At the early endosome membrane, the PAS complex, consisting of 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).

在早期内质网膜上，PAS复合体（由含FYVE指的磷脂酰肌醇激酶（PIKFYVE）、酵母VAC14同源物（VAC14）和多磷酸磷脂酰肌醇磷酸酶，亦称SAC3（FIG4）组成）通过PIKFYVE的FYVE指与膜结合（Sbrissa等，2002，Cao等，2007）。PIKFYVE激酶成分将磷脂酰肌醇3磷酸（PI3P）磷酸化为磷脂酰肌醇3,5-二磷酸PI(3,5)P2（Sbrissa等，1999）。PAS复合体存在于细胞质中，并被招募至膜上（Sbrissa等，2007）。