title: Sarcolemma phospholipid structure investigated by immunogold electron microscopy and (31)P NMR spectroscopy with lanthanide ions.
abstract: The biological functions of plasma membranes depend greatly on the biophysical properties resulting from protein and phospholipid structure. We investigated the phospholipid structure of the normal sarcolemma membrane, which is known to be highly dysfunctional in myopathies. Combining electron microscopy and (31)P nuclear magnetic resonance (NMR) spectroscopy on isolated sarcolemma vesicles, we find that (i) the sarcolemma vesicles maintain the in-vivo cellular sidedness, (ii) the phospholipid mobility is close to that observed in model membranes (similar lateral diffusion coefficients and spin-lattice T(1) relaxation times). Using broad-band and magic angle spinning (31)P NMR spectroscopy with lanthanide ions (Pr(3+)), it is possible to quantify the distribution of phospholipids between internal and external membrane layers, showing that the trans-bilayer distribution is highly asymmetrical.
authors.affiliation: Laboratoire de RMN en Biologie et Médecine (LRMBM-UPRES 2230), Faculté de Médecine, Rennes, France. celine.moreau@univ-rennes1.fr
authors.forename: C
authors.initials: C
authors.lastname: Moreau
authors.forename: A
authors.initials: A
authors.lastname: Cavalier
authors.forename: M
authors.initials: M
authors.lastname: Le Floch
authors.forename: J
authors.initials: J
authors.lastname: Segalen
authors.forename: C
authors.initials: C
authors.lastname: Rocher
authors.forename: M
authors.initials: M
authors.lastname: Traïkia
authors.forename: G
authors.initials: G
authors.lastname: Leray
authors.forename: A
authors.initials: A
authors.lastname: Bondon
authors.forename: D
authors.initials: D
authors.lastname: Thomas
authors.forename: E
authors.initials: E
authors.lastname: Le Rumeur
mesh_terms: D016764:Cell Polarity; D007150:Immunohistochemistry / Q000379:methods*; D028581:Lanthanoid Series Elements / Q000378:metabolism*; D008051:Lipid Bilayers / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008854:Microscopy, Electron / Q000379:methods*; D010743:Phospholipids / Q000737:chemistry*; D011868:Radioisotopes; D012508:Sarcolemma / Q000737:chemistry* / Q000648:ultrastructure*; D013997:Time Factors
chemical_list: D028581:Lanthanoid Series Elements; D008051:Lipid Bilayers; D010743:Phospholipids; D011868:Radioisotopes