PtdIns-(3,5)-P2 (1,2-dioctanoyl) (sodium salt)

PtdIns-(3,5)-P2 (1,2-dioctanoyl) sodium salt is a soluble analog of phosphatidylinositol-3,5-bisphosphate (PI(3,5)P2), a phosphoinositide crucial for regulating endosomal trafficking and lysosomal function. With shorter fatty acid chains, this dioctanoyl variant is more soluble, enabling studies on the signaling pathways where PI(3,5)P2 is implicated. This analog has proven to be particularly valuable in elucidating the regulatory mechanisms controlling endosome maturation, as PI(3,5)P2 is synthesized primarily on late endosomes and lysosomes through the action of the PIKfyve kinase. Researchers utilize this compound to explore how PI(3,5)P2 regulates key proteins involved in membrane fission, transport, and autophagy. For instance, studies have demonstrated that PI(3,5)P2 recruits the TRPML1 calcium channel to late endosomes, affecting lysosomal ion homeostasis. Furthermore, it interacts with the CORVET and HOPS tethering complexes to control endosome-vacuole fusion. It also plays a role in membrane trafficking related to autophagy, serving as a signal for the formation and maturation of autophagosomes. This compound is instrumental in competitive binding assays to understand the interaction between phosphoinositide-binding proteins and PI(3,5)P2. It has further helped researchers dissect the enzymatic regulation of PIKfyve and its antagonistic phosphatase, Fig4, providing insights into phosphoinositide metabolism.