Distribution of anionic sites on surface of B cell granule and plasma membranes: a study using cationic ferritin

1977 ◽  
Vol 27 (1) ◽  
pp. 289-301
Author(s):  
S.L. Howell ◽  
M. Tyhurst
Keyword(s):  
B Cell ◽  
Plasma Membranes ◽  
Calcium Concentration ◽  
Anionic Sites ◽  
Neuraminidase Treatment ◽  
Visual Probe ◽  
Cell Plasma ◽  
Granule Membrane ◽  
Pancreatic B Cells ◽  
Storage Granules

The distribution of anionic sites on the membranes of rat pancreatic B cells and of their storage granules has been studied by the use of a visual probe of cationic ferritin. Membranes of isolated storage granules possessed a net negative charge which was apparently evenly distributed; the number of anionic sites was not markedly altered by prior incubation of the granules with neuraminidase or with 10(−5) to 2 X 10(−3) M calcium chloride. Distribution of charges along B cell plasma membranes was less uniform but was similarly unaffected by alterations of calcium concentration, or by neuraminidase treatment. However, during the fusion of plasma membrane and granule membrane which occurs in exocytosis, the emerging granule membrane was found to be devoid of anionic sites. The implications of these findings for the regulation of insulin secretion by exocytosis are discussed.

scholarly journals Insulin-induced rapid decrease of a major protein in fat cell plasma membranes.

1984 ◽  
Vol 259 (19) ◽  
pp. 12112-12116
Author(s):  
E J Schoenle ◽  
L D Adams ◽  
D W Sammons
Keyword(s):  
Plasma Membranes ◽  
Rapid Decrease ◽  
Major Protein ◽  
Fat Cell ◽  
Cell Plasma

scholarly journals Charged anaesthetics alter LM-fibroblast plasma-membrane enzymes by selective fluidization of inner or outer membrane leaflets

1986 ◽  
Vol 239 (2) ◽  
pp. 301-310 ◽  
Author(s):  
W D Sweet ◽  
F Schroeder
Keyword(s):  
Plasma Membrane ◽  
Active Site ◽  
Plasma Membranes ◽  
Local Anaesthetics ◽  
Cationic Drugs ◽  
Cell Plasma ◽  
Composition And Structure ◽  
Highly Sensitive ◽  
Functional Consequences ◽  
Anionic Drugs

The functional consequences of the differences in lipid composition and structure between the two leaflets of the plasma membrane were investigated. Fluorescence of 1,6-diphenylhexa-1,3,5-triene(DPH), quenching, and differential polarized phase fluorimetry demonstrated selective fluidization by local anaesthetics of individual leaflets in isolated LM-cell plasma membranes. As measured by decreased limiting anisotropy of DPH fluorescence, cationic (prilocaine) and anionic (phenobarbital and pentobarbital) amphipaths preferentially fluidized the cytofacial and exofacial leaflets respectively. Unlike prilocaine, procaine, also a cation, fluidized both leaflets of these membranes equally. Pentobarbital stimulated 5′-nucleotidase between 0.1 and 5 mM and inhibited at higher concentrations, whereas phenobarbital only inhibited, at higher concentrations. Cationic drugs were ineffective. Two maxima of (Na+ + K+)-ATPase activation were obtained with both anionic drugs. Only one activation maximum was obtained with both cationic drugs. The maximum in activity below 1 mM for all four drugs clustered about a single limiting anisotropy value in the cytofacial leaflet, whereas there was no correlation between activity and limiting anisotropy in the exofacial leaflets. Therefore, although phenobarbital and pentobarbital below 1 mM fluidized the exofacial leaflet more than the cytofacial leaflet, the smaller fluidization in the cytofacial leaflet was functionally significant for (Na+ + K+)-ATPase. Mg2+-ATPase was stimulated at 1 mM-phenobarbital, unaffected by pentobarbital and slightly stimulated by both cationic drugs at concentrations fluidizing both leaflets. Thus the activity of (Na+ + K+)-ATPase was highly sensitive to selective fluidization of the leaflet containing its active site, whereas the other enzymes examined were little affected by fluidization of either leaflet.

scholarly journals A rapid immunological procedure for the isolation of hormonally sensitive rat fat-cell plasma membrane

1976 ◽  
Vol 154 (1) ◽  
pp. 11-21 ◽  
Author(s):  
J P Luzio ◽  
A C Newby ◽  
C N Hales
Keyword(s):  
Plasma Membrane ◽  
Adenylate Cyclase ◽  
Plasma Membranes ◽  
Membrane Preparation ◽  
Fat Cells ◽  
Fat Cell ◽  
Cell Plasma ◽  
Rat Fat Cells ◽  
Plasma Membrane Preparation ◽  
Isolated Rat

1. A rapid method for the isolation of hormonally sensitive rat fat-cell plasma membranes was developed by using immunological techniques. 2. Rabbit anti-(rat erythrocyte) sera were raised and shown to cross-react with isolated rat fat-cells. 3. Isolated rat fat-cells were coated with rabbit anti-(rat erythrocyte) antibodies, homogenized and the homogenate made to react with an immunoadsorbent prepared by covalently coupling donkey anti-(rabbit globulin) antibodies to aminocellulose. Uptake of plasma membrane on to the immunoadsorbent was monitored by assaying the enzymes adenylate cyclase and 5′-nucleotidase and an immunological marker consisting of a 125I-labelled anti-(immunoglobulin G)-anti-cell antibody complex bound to the cells before fractionation. Contamination of the plasma-membrane preparation by other subcellular fractions was also investigated. 4. By using this technique, a method was developed allowing 25-40% recovery of plasma membrane from fat-cell homogenates within 30 min of homogenization. 5. Adenylate cyclase in the isolated plasma-membrane preparation was stimulated by 5 μm-adrenaline.

scholarly journals Sendai-viral HN and F glycoproteins as probes of plasma-membrane protein catabolism in HTC cells. Studies with fusogenic reconstituted Sendai-viral envelopes

1987 ◽  
Vol 241 (3) ◽  
pp. 801-807 ◽  
Author(s):  
R T Earl ◽  
E E Billett ◽  
I M Hunneyball ◽  
R J Mayer
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Plasma Membranes ◽  
Viral Proteins ◽  
Plasma Membrane Protein ◽  
Lysosomal Degradation ◽  
Cell Plasma ◽  
Degradation Rates ◽  
Htc Cells ◽  
Viral Envelopes

Reconstituted Sendai-viral envelopes (RSVE) were produced by the method of Vainstein, Hershkovitz, Israel & Loyter [(1984) Biochim. Biophys. Acta 773, 181-188]. RSVE are fusogenic unilamellar vesicles containing two transmembrane glycoproteins: the HN (haemagglutinin-neuraminidase) protein and the F (fusion) factor. The fate of the viral proteins after fusion-mediated transplantation of RSVE into hepatoma (HTC) cell plasma membranes was studied to probe plasma-membrane protein degradation. Both protein species are degraded at similar, relatively slow, rates (t1/2 = 67 h) in HTC cells fused with RSVE in suspension. Even slower degradation rates for HN and F proteins (t1/2 = 93 h) were measured when RSVE were fused with HTC cells in monolayer. Lysosomal degradation of the transplanted viral proteins is strongly implicated by the finding that degradation of HN and F proteins is sensitive to inhibition by 10 mM-NH4Cl (81%) and by 50 micrograms of leupeptin/ml (70%).

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