Role of sphingomyelin in membrane-domain formation and the influence on protein interaction: focusing on the nanometer scale

ROMINA VAZQUEZ; VANESA HERLAX; SABINA MATÉ; LAURA BAKÁS

Membrane organization and lipid rafts in the cell and artificial membranes

Nova Science Publishers

Lugar: Nueva York; Año: 2016; p. 89 - 112

The advent of novel experimental techniques based onphysical principles opens a window to the nanometer world facilitating arenewed and detailed study of membranes. These specific techniques enable anunderstanding of how biologic-membrane functioning is related to membranephysical properties on various scales of time and dimension.A preferential interaction between sphingomyelin (SM)and cholesterol (Cho) in both cell and model membranes has been proposed as akey influence on the formation of Cho- and SM-rich membrane domains. Thischapter provides insights into the lateral structure and molecular organizationof lipid membranes on the nanometer scale. We focus on how the specificmolecular structure of SM affects the lateral behavior and physical propertiesof both model and natural membranes.In addition, the lateral structure controls themechanical properties of the membrane and thereby protein-membraneinteractions. Many proteins, targeted to membrane microdomains by favorableassociations with ordered lipids, are linked to the saturated acyl chains thatpartition well into these domains. This chapter shows, on the nanometer scale,the interaction with membranes of alpha-hemolysin(HlyA), an acylated protein. Atomic-force?microscopy images indicated that theHlyA interaction appears not to conform to the general strategy described forother invasive proteins.