Lysophosphatidic acid lysophosphatidylcholine

Lecithins and related phospholipids usually contain a saturated fatty acid in the C-1 position but an rmsaturated acid, which may contain from one to four double bonds, at C-2. Arachidonic acid is often present here. Hydrolysis of the ester linkage at C-2 yields a l-acyl-3-phosphoglycerol, better known as a lysophosphatidylcholine. The name comes from the powerful detergent action of these substances which leads to lysis of cells. Some snake venoms contain phospholipases that form lysophosphatidylcholine. Lysophosphatidic acid (l-acyl-glycerol-3-phosphate) is both an intermediate in phospholipid biosynthesis (Chapter 21) and also a signaling molecule released into the bloodstream by activated platelets. ... 

Fig. 1 Chemical structures of some of the bioactive phospholipids and FTY720/FTY720-P. LPA lysophosphatidic acid, SIP sphingosine 1-phosphate, LPC lysophosphatidylcholine, SPC sphingosylphosphorylcholine...

Baker RR, Chang H (2000) A metabolic path for the degradation of lysophosphatidic acid, an inhibitor of lysophosphatidylcholine lysophospholipase, in neuronal nuclei of cerebral cortex. Biochim Biophys Acta 1483 58-68... 

All of the above SMases are C type SMases that produce Cer and choline phosphate an SMase D (which produces Cer 1-phosphate and choline) is found in the venom of brown recluse spider, Corynebacterium pseudotuberculosis (which commonly infects sheep). Vibrio damsela (an aquatic bacterium that causes wound infections in humans), and the human pathogen Arcanobacterium haemolyticum. The venom SMase D produces much of the tissue damage caused by these organisms (A.P Truett, 1993) by sustained activation of inflammation (S.H. Farsky, 2005). Interestingly, SMase also acts as a lysophosphatidylcholine phosphodiesterase to produce lysophosphatidic acid, another inflammatory mediator (L.A. van Meeteren, 2004). 

Figure 2. Effect of various lipids on DGAT activity in the 0.5% Triton X-100 extract. CL, cardiolipin G3P, glycerol-3-phosphate LPC, lysophosphatidylcholine ITS, lysophosphatidylserine LPA, lysophosphatidic acid.

Figure 4. Lysophosphatidic acid (LPA) metabolism at the plasma membrane. LPAAT, lysophosphatidic acid acyl transferase. lysoPtdCho, lysophosphatidylcholine. PLA2, phospholipase A. PtdCho, phosphatidylcholine.

Zhao, Z. and Xu, Y. (2009) Measurement of endogenous lysophosphatidic acid by ESI-MS/MS in plasma samples requires pre-separation of lysophosphatidylcholine. J. 

DAG, diacylglycerols FFA, free fatty acids LPA/PA, lysophosphatidic adds/phosphatidic acids LPC/PC, lysophosphatidylcholines/phosphatidylcholines MAG, monoacylglyce-rols PE, phosphatidylethanolamines TAG, triacylglycerols. nd = not detected... 

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