Alterations in membrane dynamics elicited by amphiphilic compounds are augmented in plasmenylcholine bilayers

The dynamics of binary mixtures of choline glycerophospholipids and lysophospholipids were examined by fluorescence spectroscopy to compare and contrast the effects of each subclass of lysophospholipids on plasmenylcholine and phosphatidylcholine membrane motional characteristics. The decrease in steady-state anisotropy resulting from the introduction of lysoplasmenylcholine into plasmenylcholine bilayers was 4-6-fold greater than that manifest from the introduction of lysophosphatidylcholine into phosphatidylcholine bilayers (i.e., delta r = 0.017 vs. 0.004 or 0.011 vs. 0.002 at 5 C degrees and 10 C degrees above their phase transition temperatures, respectively). Lysoplasmenylcholine was also more potent than lysophosphatidylcholine in perturbing the dynamics of membrane bilayers comprised of phosphatidylcholine as measured by alterations in the steady-state anisotropy of the diphenylhexatriene probe. Finally, lipid matrices comprised of plasmenylcholine were uniformly more susceptible to amphiphilic perturbation (mediated by lysoplasmenylcholine, lysophosphatidylcholine or long chain acylcarnitine) than matrices comprised of phosphatidylcholine. Collectively, these results demonstrate that accumulation of plasmalogen catabolites resulting from activation of plasmalogen-selective phospholipases A2 can potentiate alterations in membrane dynamics during signal transduction in plasmalogen-enriched bilayers.