Hydrolyzes the ester bond at the sn-1 position of glycerophospholipids and produces 2-acyl lysophospholipids, being phosphatidylinositol (PI) its major substrate. PI is a versatile lipid that not only serves as a structural component of cellular membranes, but also plays important roles in signal transduction through distinct phosphorylated derivatives of the inositol head group (PubMed:20668164). Catalyzes the hydrolysis of phosphatidylcholine at sn-2 position in vitro (PubMed:23007400). Regulates asymmetric division, an important property of stem cells in C.elegans, by controlling the subcellular localizations of beta-catenin (PubMed:18497747, PubMed:20668164). 1,2-dihexadecanoyl-sn-glycero-3-phospho-(1D-myo-inositol) + H2O = 2-hexadecanoyl-sn-glycero-3-phospho-(1D-myo-inositol) + H(+) + hexadecanoate a 1,2-diacyl-sn-glycero-3-phospho-L-serine + H2O = a 2-acyl-sn-glycero-3-phospho-L-serine + a fatty acid + H(+) 1-hexadecanoyl-2-(9Z-octadecenoyl)-sn-glycero-3-phospho-L-serine + H2O = 2-(9Z-octadecenoyl)-sn-glycero-3-phospho-L-serine + H(+) + hexadecanoate 1,2-di-(9Z-octadecenoyl)-sn-glycero-3-phosphocholine + H2O = (9Z)-octadecenoate + (9Z-octadecenoyl)-sn-glycero-3-phosphocholine + H(+) a 1,2-diacyl-sn-glycero-3-phosphocholine + H2O = a 1-acyl-sn-glycero-3-phosphocholine + a fatty acid + H(+) 1,2-dihexadecanoyl-sn-glycero-3-phosphocholine + H2O = 1-hexadecanoyl-sn-glycero-3-phosphocholine + H(+) + hexadecanoate Inhibited by E-6-bromomethylene-3-1-naphthalenyl-2H-tetrahydropyran-2-one (BEL) in vitro. Belongs to the PA-PLA1 family.