Fluorogenic phospholipid substrate to detect lysophospholipase D/autotaxin activity.

[reaction: see text] Lysophospholipase D (lysoPLD), also known as autotaxin (ATX), is an important source of the potent mitogen lysophosphatidic acid (LPA). Two fluorogenic substrate analogues for lysoPLD were synthesized in nine steps from (S)-PMB-glycerol. The substrates (FS-2 and FS-3) show significant increases in fluorescence when treated with recombinant ATX and have potential applications in screening for this emerging drug target.

Phosphoinositide-containing polymerized liposomes: stable membrane-mimetic vesicles for protein-lipid binding analysis.

Stable phosphoinositide (PIP(n))-containing liposomes were prepared using polydiacetylene photochemistry. Tethered pentacosadiynyl inositol polyphosphate (InsP(n)) analogues of Ins(1,3,4)P(3), Ins(1,4,5)P(3), and Ins(1,3,4,5)P(4) were synthesized, incorporated into vesicles made up of diyne-phosphatidylcholine and -phosphatidylethanolamine, and polymerized by UV irradiation. The polymerized liposome nanoparticles showed markedly increased stability over conventional PIP(n)-containing vesicles as a result of the covalent conjugated ene-yne network in the acyl chains. The polymerized liposomes were specifically recognized by PIP(n) binding PH domains in liposome overlay assays and amplified luminescent proximity homogeneous assays. Moreover, the biotin moiety allowed attachment of the nanoparticles to a streptavidin-coated sensor chips in surface plasmon resonance (SPR) sensor. The PIP(n) headgroups displayed on SPR sensors showed higher affinities for PH domains and PIP(n) monoclonal antibodies than did monomeric PIP(n)-analogues with biotinylated acyl chains.