PA, LPA & Cyclic LPA

Phosphatidic acid (PA) and lysophosphatidic acid (LPA) are two types of important anionic bioactive lipids. They play a role in many cellular processes. LPA has a more negative charge than PA in the lipid bilayer. This is probably because of the hydroxyl group on LPA's backbone and how it interacts with the phosphomonoester headgroup. The charge of PA or LPA depends on the local lipid composition in the bilayer. PA and LPA have hydrogen bond properties that help with their various cellular functions. Cyclic PA is like LPA but occurs naturally in the body. It affects different cellular functions, like regulating cell growth, causing stress fiber formation, preventing tumor cell invasion, and regulating the survival of neurons. Interestingly, the effects of cyclic PA seem to oppose those of LPA. Scientists have found cyclic PA in human serum albumin. They used a technique called ESI-MS/MS analysis and found that 16:0 cyclic PA was the most common type, with 14:0 and 18:0 cyclic PA found in smaller amounts.