MEMBRANE RESTRUCTURING EVENTS DURING THE ENZYMATIC GENERATION OF CERAMIDES WITH VERY LONG-CHAIN POLYUNSATURATED FATTY ACIDS

PEÑALVA, DANIEL ALEJANDRO; ANTOLLINI, SILVIA; AMBROGGIO, ERNESTO; AVELDAÑO, MARTA I.; FANANI, MARIA LAURA

LANGMUIR

AMER CHEMICAL SOC

Año: 2018

0743-7463

n rat sperm head, sphingomyelin (SM) species that contain very long chain PUFA (V-SM) become ceramides (V-Cer) after inducing in vitro the acrosomal reaction. The reason for such a specific location of this conversion, catalysed by a sphingomyelinase (SMase), has received little investigation so far. Here, the effects of SMase were compared in unilamellar vesicles (LUVs, GUVs) containing phosphatidylcholine and either V-SM or a palmitate-rich SM (P-SM). In uniformly sized LUVs at 37 °C, more V-Cer was generated, and more rapidly, than P-Cer. Nephelometry and dynamic light scattering showed that LUVs tended to form large lipid particles more intensely, and FRET increases suggested that lateral lipid mixing was more marked when V-Cer rather than P-Cer was produced. As reported by Laurdan and DPH, the production of V-Cer resulted in higher and faster restriction in lipid mobility than that of P-Cer, implying a stronger increase in membrane dehydration and microviscosity. Moreover, DPH an