Endogenous Expression of the Class I Phosphatidylinositol Transfer Protein PPIT-2 in Caenorhabditis elegans.

Phosphatidylinositol transfer proteins (PITPs) transfer phosphatidylinositol (PI) between the ER and target membranes to regulate phosphoinositide metabolism. However, the expression patterns of class I PITPs in C. elegans remain largely uncharacterized. Here, we generated an endogenous GFP knock-in reporter for PPIT-2 (formerly Y71G12B.17), a conserved homolog of human PITPNA and PITPNB. GFP::PPIT-2 was prominently expressed in the excretory system and canals, with additional expression in the hypodermis, sperm, developing vulva, and germline-adjacent pseudocoelom. PPIT-2 expression notably overlaps with fatty acid synthase FASN-1, establishing candidate tissues to investigate its roles in PI transfer, membrane trafficking, and lipid homeostasis.