title: Microscopy of membrane lipids: how precisely can we define their distribution?
abstract: Membrane lipids form the basic framework of biological membranes by forming the lipid bilayer, but it is becoming increasingly clear that individual lipid species play different functional roles. However, in comparison with proteins, relatively little is known about how lipids are distributed in the membrane. Several microscopic methods are available to study membrane lipid dynamics in living cells, but defining the distribution of lipids at the submicrometre scale is difficult, because lipids diffuse quickly in the membrane and most lipids do not react with aldehydes that are commonly used as fixatives. Quick-freezing appears to be the only practical method by which to stop the lipid movement instantaneously and capture the molecular localization at the moment of interest. Electron microscopic methods, using cryosections, resin sections, and freeze-fracture replicas are used to visualize lipids in quick-frozen samples. The method that employs the freeze-fracture replica is unique in that it requires no chemical treatment and provides a two-dimensional view of the membrane.
authors: Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan.
authors: Sho
authors: S
authors: Takatori
authors: Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan.
authors: Toyoshi
authors: T
authors: Fujimoto
mesh_terms: D000447:Aldehydes / Q000737:chemistry; D002462:Cell Membrane / Q000737:chemistry / Q000648:ultrastructure*; D004058:Diffusion; D004853:Epoxy Resins; D005614:Freeze Fracturing / Q000295:instrumentation / Q000379:methods; D017979:Gold Colloid / Q000737:chemistry; D008563:Membrane Lipids / Q000737:chemistry*; D008565:Membrane Proteins / Q000737:chemistry; D008854:Microscopy, Electron; D008867:Microtomy; D009942:Organometallic Compounds / Q000737:chemistry; D013194:Staining and Labeling / Q000379:methods*; D016707:Tissue Fixation / Q000379:methods*
chemical_list: D000447:Aldehydes; D004853:Epoxy Resins; D017979:Gold Colloid; D008563:Membrane Lipids; D008565:Membrane Proteins; D009942:Organometallic Compounds; C005460:uranyl acetate