Lipid-modulating phosphodiesterase (PubMed:26095358). Active on the surface of macrophages and dendritic cells and strongly influences macrophage lipid composition and membrane fluidity. Acts as a negative regulator of Toll-like receptor signaling (By similarity). Has in vitro phosphodiesterase activity, but the physiological substrate is unknown (PubMed:26095358). Lacks activity with phosphocholine-containing lipids, but can cleave CDP-choline, and can release phosphate from ATP and ADP (in vitro) (By similarity). Binds 2 Zn(2+) ions per subunit. Interacts with TLR4, TLR7, TLR8 and TLR9. N-glycosylated. Belongs to the acid sphingomyelinase family.