查看文章

The local generation of phosphatidic acid plays a key role in the regulation of intracellular membrane transport through mechanisms which are largely unknown. Phosphatidic acid may recruit and activate downstream effectors, or change the biophysical properties of the membrane and directly induce membrane bending and/or destabilization. To evaluate these possibilities, we determined the phase properties of phosphatidic acid and lysophosphatidic acid at physiological conditions of pH and ion concentrations. In single‐lipid systems, unsaturated phosphatidic acid behaved as a cylindrical, bilayer‐preferring lipid at cytosolic conditions (37 °C, pH 7.2, 0.5 mm free Mg²⁺), but acquired a type‐II shape at typical intra‐Golgi conditions, a mildly acidic pH and submillimolar free Ca²⁺ (pH 6.6–5.9, 0.3 mm Ca²⁺). Lysophosphatidic acid formed type‐I lipid micelles in the absence of divalent cations, but anhydrous …