scholarly journals Mobility and detergent extractability of acetylcholine receptors on cultured rat myotubes: a correlation.

1983 ◽  
Vol 97 (1) ◽  
pp. 48-51 ◽  
Author(s):  
M Stya ◽  
D Axelrod
Keyword(s):  
New York ◽  
Acetylcholine Receptors ◽  
Lipid Membrane ◽  
Metabolic Inhibitors ◽  
Fluorescence Photobleaching Recovery ◽  
Cytoplasmic Proteins ◽  
Detergent Extraction ◽  
Photobleaching Recovery ◽  
Recovery Technique ◽  
B Mobility

On aneurally cultured rat primary myotubes, 10% of the acetylcholine receptors (AChR) are found aggregated and immobilized in endogenous clusters. The remaining receptors are diffusely distributed over the cell membrane and the majority of these are free to diffuse in the plane of the membrane. This study correlates the mobility of AChR (as measured with the fluorescence photobleaching recovery technique, FPR) with the detergent extractability of this receptor. Gentle detergent extraction of the cells removes the lipid membrane and the soluble cytoplasmic proteins but leaves an intact cytoskeletal framework on the substrate. Two studies indicate a correlation between mobility and extractability: (a) mobility of diffusely distributed AChR decreases as myotubes age in culture; previous work showed that extractability of AChR decreases as myotubes age in culture (Prives, J., C. Christian, S. Penman, and K. Olden, 1980, In Tissue Culture in Neurobiology, E. Giacobini, A. Vernadakis, and A. Shahar, editors, Raven Press, New York, 35-52); (b) mobility of clustered AChR increases when cells are treated with metabolic inhibitors such as sodium azide (NaN3); extractability of clustered AChR also increases with this treatment. From these results we suggest the involvement of a cytoskeletal framework in the immobilization of AChR on the cell surface.

scholarly journals A factor from neurons induces partial immobilization of nonclustered acetylcholine receptors on cultured muscle cells.

1981 ◽  
Vol 88 (2) ◽  
pp. 459-462 ◽  
Author(s):  
D Axelrod ◽  
H C Bauer ◽  
M Stya ◽  
C N Christian
Keyword(s):  
Conditioned Medium ◽  
Acetylcholine Receptors ◽  
Glioma Cell ◽  
Primary Cultures ◽  
Glioma Cell Line ◽  
Continuous Treatment ◽  
Hybrid Cells ◽  
Fluorescence Photobleaching Recovery ◽  
Photobleaching Recovery ◽  
Alpha Bungarotoxin

A factor or factors released by cultured NG108-15 neuroblastoma X glioma hybrid cells and added to the medium of rat myotube primary cultures was found to immobilize some of the previously mobile acetylcholine receptors in the myotube membrane. Partial receptor immobilization occurred within 3 h after the beginning of treatment with the NG108-15-conditioned medium factor and persisted for at least 24 h of continuous treatment. A similarly derived conditioned medium concentrate from the non-neuronal parent glioma cell line did not immobilize receptors, relative to untreated controls. Acetylcholine receptors were visualized by fluorescent alpha-bungarotoxin and their lateral motion was observed by the technique of fluorescence photobleaching recovery.

scholarly journals Na+,K+-adenosine triphosphatase polarity in retinal photoreceptors: a role for cytoskeletal attachments.

1989 ◽  
Vol 109 (4) ◽  
pp. 1483-1493 ◽  
Author(s):  
S A Madreperla ◽  
M Edidin ◽  
R Adler
Keyword(s):  
Photoreceptor Cells ◽  
Fluorescence Photobleaching Recovery ◽  
Retinal Photoreceptors ◽  
Quantitative Image ◽  
Detergent Extraction ◽  
Photobleaching Recovery ◽  
Alpha Spectrin ◽  
Asymmetrically Distributed ◽  
In Cells

We have used isolated embryonic photoreceptor cells as a model system with which to examine the mechanisms responsible for the development and maintenance of asymmetric Na+,K+-ATPase (ATPase) distribution. Photoreceptor precursors, which appear round and process free at culture onset, develop structural and molecular properties similar to those of photoreceptor cells in vivo. ATPase, recognized by an anti-ATPase antibody, is distributed over the entire surface of round photoreceptor precursors. As the cells develop, ATPase becomes progressively concentrated in the inner segment (where it is found in cells of the intact retina). This phenomenon occurs in cells developing in the absence of intercellular contacts. The development of ATPase polarity correlates with a decrease in the fraction of ATPase molecules that are mobile in the membrane (as determined by fluorescence photobleaching recovery), as well as with an increase in the fraction of ATPase that remains associated with the cells after detergent extraction. The magnitudes of the mobile ATPase fractions agree well with those of the detergent-extractable fractions in both the immature and developed photoreceptors. The distribution of alpha spectrin and ATPase-immunoreactive materials appeared qualitatively similar, and quantitative image analysis showed similar gradients of spectrin and Na+,K+-ATPase immunofluorescence along the long axis of elongated photoreceptors. Moreover, detergent extractability of alpha spectrin and the ATPase showed similar modifications in response to changes in pH or KCl concentration. ATPase detergent-extractable and mobile fractions were not changed in cultures treated with cytoskeletal inhibitors such as nocodazole. These data are consistent with a role for an asymmetrically distributed, spectrin-containing subcortical cytoskeleton in the preferential accumulation of Na+,K+-ATPase in the photoreceptor inner segment.

What do nanometer molecular trajectories tell us about heterogeneous cell surface domaines?

1995 ◽  
Vol 53 ◽  
pp. 786-787
Author(s):  
Watt W. Webb
Keyword(s):  
Cell Surface ◽  
Lipid Membranes ◽  
Surface Proteins ◽  
Protein Diffusion ◽  
Coated Pits ◽  
Cell Surface Proteins ◽  
Membrane Heterogeneity ◽  
Fluorescence Photobleaching Recovery ◽  
Photobleaching Recovery ◽  
Plasma Membrane Heterogeneity

Plasma membrane heterogeneity is implicit in the existence of specialized cell surface organelles which are necessary for cellular function; coated pits, post and pre-synaptic terminals, microvillae, caveolae, tight junctions, focal contacts and endothelial polarization are examples. The persistence of these discrete molecular aggregates depends on localized restraint of the constituent molecules within specific domaines in the cell surface by strong intermolecular bonds and/or anchorage to extended cytoskeleton. The observed plasticity of many of organelles and the dynamical modulation of domaines induced by cellular signaling evidence evanescent intermolecular interactions even in conspicuous aggregates. There is also strong evidence that universal restraints on the mobility of cell surface proteins persist virtually everywhere in cell surfaces, not only in the discrete organelles. Diffusion of cell surface proteins is slowed by several orders of magnitude relative to corresponding protein diffusion coefficients in isolated lipid membranes as has been determined by various ensemble average methods of measurement such as fluorescence photobleaching recovery(FPR).

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