Analysis of lipid-composition changes in plasma membrane microdomains

Abstract

This article is available online at http://www.jlr.org and cholesterol (Chol) ( 1-5 ). These sphingolipid-rich microdomains are considered to be important sites for signal transduction and death receptor functions ( 6, 7 ). Depending on the local microenvironment, certain membrane proteins are preferentially localized inside (or outside) of the microdomains and serve as signaling platforms (8)(9)(10)(11)(12)(13)(14)(15)(16)(17). Recent data has indicated that membrane microdomains are dynamic nanometer-sized domains ( 18,19 ). Results from image analysis and single-molecule tracking studies have shown that these metastable membrane assemblies can be stabilized locally by lipid-lipid and lipidprotein interactions to coalesce and form functional domains and facilitate cell surface receptor signal transduction. A commonly held view is that microdomains regulate membrane protein functions by recruiting signaling molecules to the spatially limited region ( 7,20,21 ).Tight interactions between Chol and SM result in the formation of domains that are resistant to solubilization with detergents ( 22 ). This property is often used to prepare membrane microdomains. The typical preparation method involves the treatment of postnuclear lysates, generated by the removal of nuclei from cell lysates, with a nonionic detergent at low temperature, followed by separation of the low-density lipid fraction in a sucrose gradient ( 1 ). However, this fraction may contain a broad range of detergent-resistant membranes other than plasma membrane microdomains. Therefore, concerns have been raised that results obtained using this conventional method are not limited to events occurring on plasma membrane Membrane microdomains, including caveolae or lipid rafts, are plasma membrane domains that contain enhanced levels of sphingolipids, saturated fatty-acyl glycerophospholipids,

Sphingomyelin generated by sphingomyelin synthase 1 is involved in attachment and infection with Japanese encephalitis virus

“…Lipid extraction from tMEFs or mouse brain and measurements of ceramide species in lipid extracts were performed using LC-MS/MS as described previously4243. The amounts of SM and ceramide species with various carbon chains (d18:1/16:0, d18:0/16:0, d18:1/18:1, d18:1/18:0, d18:1/20:1, d18:1/20:0, d18:1/22:1, d18:1/22:0, d18:1/24:1, d18:1/24:0, d18:1/26:1, d18:1/26:0, d16:1/18:1, d16:1/20:0, and d18:2/16:0 h) were determined.…”

The mystery of membrane organization: composition, regulation and roles of lipid rafts

“…Mass spectroscopy (Fig. 2b), for instance, is one the most accurate tools to address the lipid and protein composition of membranes without the necessity of external labelling 65 , and has been used for label-free determination of membrane domain composition in model and cell-derived membranes 66–71 . iSCAT microscopy has also facilitated label-free observation of the dynamics of ordered domains in model membranes 72 .…”

Membrane lipids and cell signaling

“…For example, glycerolphospholipids have been shown to regulate vesicular transport. The sorting of glycosylphosphatidylinositol lipid anchors in the endoplasmic reticulum and sphingolipids can change the ability of SNAREs (soluble N-ethylmaleimide sensitive fusion [NSF] attachment protein receptors) to promote membrane fusion [34, 35]. …”