title: Lateral movements of membrane glycoproteins restricted by dynamic cytoplasmic barriers.
abstract: Cell membranes often are patchy, composed of lateral domains. These domains may be formed by barriers within or on either side of the membrane bilayer. Major histocompatibility complex (MHC) class 1 molecules that were either transmembrane- (H-2Db) or glycosylphosphatidylinositol (GPI)-anchored (Qa2) were labeled with antibody-coated gold particles and moved across the cell surface with a laser optical tweezers until they encountered a barrier, the barrier-free path length (BFP). At room temperature, the BFPs of Qa2 and H-2Db were 1.7 +/- 0.2 and 0.6 +/- 0.1 (micrometers +/- SEM), respectively. Barriers persisted at 34 degrees C, although the BFP for both MHC molecules was fivefold greater at 34 degrees C than at 23 degrees C. This indicates that barriers to lateral movement are primarily on the cytoplasmic half of the membrane and are dynamic.
authors.affiliation: Department of Biology, Johns Hopkins University, Baltimore, MD 21218.
authors.forename: M
authors.initials: M
authors.lastname: Edidin
authors.forename: S C
authors.initials: SC
authors.lastname: Kuo
authors.forename: M P
authors.initials: MP
authors.lastname: Sheetz
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D002460:Cell Line; D006017:Glycolipids / Q000502:physiology; D017261:Glycosylphosphatidylinositols; D006046:Gold; D006183:H-2 Antigens / Q000502:physiology*; D015395:Histocompatibility Antigens Class I / Q000502:physiology*; D008051:Lipid Bilayers; D008562:Membrane Glycoproteins / Q000502:physiology*; D051379:Mice; D010716:Phosphatidylinositols / Q000502:physiology; D013816:Thermodynamics; D014162:Transfection
chemical_list: D000911:Antibodies, Monoclonal; D006017:Glycolipids; D017261:Glycosylphosphatidylinositols; D006183:H-2 Antigens; D015395:Histocompatibility Antigens Class I; D008051:Lipid Bilayers; D008562:Membrane Glycoproteins; D010716:Phosphatidylinositols; C032907:Q surface antigens; D006046:Gold