Glycolipids: Linchpins in the Organization and Function of Membrane Microdomains

Abstract

Membrane microdomains, also called lipid rafts, are areas on membrane enriched in glycolipids, sphingolipids, and cholesterol. Although membrane microdomains are thought to play key roles in many cellular functions, their structures, properties, and biological functions remain obscure. Cellular membranes contain several types of glycoproteins, glycolipids, and other lipids, including cholesterol, glycerophospholipids, and sphingomyelin. Depending on their physicochemical properties, especially the characteristics of their glycolipids, various microdomains form on these cell membranes, providing structural or functional contextures thought to be essential for biological activities. For example, the plasma membranes of human neutrophils are enriched in lactosylceramide (LacCer) and phosphatidylglucoside (PtdGlc), each of which forms different membrane microdomains with different surrounding molecules and is involved in different functions of neutrophils. Specifically, LacCer forms Lyn-coupled lipid microdomains, which mediate neutrophil chemotaxis, phagocytosis, and superoxide generation, whereas PtdGlc-enriched microdomains mediate neutrophil differentiation and spontaneous apoptosis. However, the mechanisms by which these glycolipids form different nano/meso microdomains and mediate their specialized functions remain incompletely understood. This review describes current understanding of the roles of glycolipids and sphingolipids in their enriched contextures on cellular membranes, including their mechanisms of facilitation and regulation of intracellular signaling. This review also introduces new concepts about the roles of glycolipid and sphingolipiddependent contextures in immunological functions.

The Structures of Heterogeneous Membranes and Their Interactions with an Anticancer Peptide: A Molecular Dynamics Study

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SLAPSHOT reveals rapid dynamics of extracellularly exposed proteome in response to calcium-activated plasma membrane phospholipid scrambling

“…As revealed by our MS data, SLAPSHOT labels only tyrosine and tryptophan residues ( Supplementary Figure S6 ), whose collective abundance as well as the fraction exposed to solvent is lower than those of lysines that are targeted by NHS-chemistry (Fiser and Simon, 2000; Sherchand et al, 2016). Furthermore, the microscopically detected CSC labeling intensity is inflated by the numerous and polymeric glycans decorating a large fraction of plasma membrane proteins (Schjoldager et al, 2020) as well as by the abundant plasma membrane glycolipids (Hanafusaet al, 2020). Taken together, these results demonstrate the feasibility and fidelity of SLAPSHOT labeling on living cells in shorter timescales than other technologies, without compromising the integrity of plasma membrane.…”

How smell regulates metabolism: The role of ectopically expressed olfactory receptors in lipid and glucose homeostasis

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