Electrophoretic movement and localization of acetylcholine receptors in the embryonic muscle cell membrane

Nature ◽  
1978 ◽  
Vol 275 (5675) ◽  
pp. 31-35 ◽  
Author(s):  
Norman Orida ◽  
Mu-ming Poo
Keyword(s):  
Cell Membrane ◽  
Muscle Cell ◽  
Acetylcholine Receptors ◽  
Embryonic Muscle ◽  
Muscle Cell Membrane

scholarly journals Particle arrays in earthworm postjunctional membranes.

1978 ◽  
Vol 76 (1) ◽  
pp. 76-86 ◽  
Author(s):  
J Rosenbluth
Keyword(s):  
Cell Membrane ◽  
Muscle Cell ◽  
Acetylcholine Receptors ◽  
Body Wall ◽  
Freeze Fracture ◽  
Body Wall Muscle ◽  
Thin Sections ◽  
Ordered Arrays ◽  
Accurate Picture ◽  
Muscle Cell Membrane

Analysis of freeze-fractured earthworm body wall muscle reveals distinctive trough-shaped concavities in the protoplasmic leaflet of the muscle cell membrane which contain diagonally oriented rows of particles sometimes in highly ordered arrays. The troughs correspond to the concave postjunctional patches of sarcolemma seen previously in thin sections of myoneural junctions identified as cholinergic, and the intramembranous particles within the troughs correspond in concentration and arrangement to granular elements present in the outer dense lamina of the postjunctional membrane which were interpreted as acetylcholine receptors. The freeze-fracture data provide a more accurate picture of the arrangement of these putative receptors within the plane of the membrane, and indicate also that they extend into the membrane at least as far as its hydrophobic layer.

scholarly journals Immunological studies of the embryonic muscle cell surface. Antiserum to the prefusion myoblast.

1979 ◽  
Vol 81 (1) ◽  
pp. 193-214 ◽  
Author(s):  
M Friedlander ◽  
D A Fischman
Keyword(s):  
Skeletal Muscle ◽  
Cell Membrane ◽  
Cell Surface ◽  
Muscle Cell ◽  
Surface Antigens ◽  
Embryonic Chick ◽  
Stages Of Development ◽  
Myogenic Cells ◽  
Embryonic Muscle ◽  
Muscle Cell Membrane

Xenogeneic antisera raised in rabbits have been used to detect compositional changes at the cell surfaces of differentiating embryonic chick skeletal muscle. In this report, we present the serological characterization of antiserum (Anti-M-24) against muscle tissue and developmental stage-specific cell surface antigens of the prefusion myoblast. Cells from primary cultures of 12-d-old embryonic chick hindlimb muscle were injected into rabbits, and the resulting antisera were selectively absorbed to obtain immunological specificity. Cytotoxicity and immunohistochemical assays were used to test this antiserum. Absorption with embryonic or adult chick heart, brain, retina, liver, erythrocytes, or skeletal muscle fibroblasts failed to remove all reactivity of Anti-M-24 for myogenic cells at all stages of development. After absorption with embryonic myotubes, however, Anti-M-24 no longer reacted with differentiated myofibers, but did react with prefusion myoblasts. The myoblast surface antigens detected with Anti-M-24 are components of the muscle cell membrane: (a) these macromolecules are free to diffuse laterally within the myoblast membrane; (b) Anti-M-24, in the presence of complement, induced lysis of the muscle cell membrane; and (c) intact monolayers of viable myoblasts completely absorbed reactivity of Anti-M-24 for myoblasts. These antigens are not loosely adsorbed culture medium components or an artifact of tissue culture because: (a) absorption of Anti-M-24 with homogenized embryonic muscle removed all antibodies to cultured myoblasts; (b) Anti-M-24 reacted with myoblast surfaces in vivo; and (c) absorption of Anti-M-24 with culture media did not affect the titer of this antiserum for myoblasts. We conclude that myogenic cells at all stages of development possess externally exposed antigens which are undetected on other embryonic and adult chick tissues. In addition, myoblasts exhibit surface antigenic determinants that are either masked, absent, or present in very low concentrations on skeletal muscle fibroblasts, embryonic myotubes, or adult myofibers. These antigens are free to diffuse laterally within the myoblast membrane and may be modulated in response to appropriate environmental cues during myodifferentiation.

scholarly journals Novel autoantibodies against muscle-cell membrane proteins in patients with myositis

1996 ◽  
Vol 39 (11) ◽  
pp. 1860-1868 ◽  
Author(s):  
Bruno Stuhlmüller ◽  
Ricardo Jerez ◽  
Gert Hausdorf ◽  
Hans-R. Barthel ◽  
Michael Meurer ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Cell Membrane ◽  
Muscle Cell ◽  
Cell Membrane Proteins ◽  
Muscle Cell Membrane

Ammonia movement and distribution after exercise across white muscle cell membranes in rainbow trout

1996 ◽  
Vol 271 (3) ◽  
pp. R738-R750 ◽  
Author(s):  
Y. Wang ◽  
G. J. Heigenhauser ◽  
C. M. Wood
Keyword(s):  
Membrane Potential ◽  
Cell Membrane ◽  
Intracellular Ph ◽  
Muscle Cell ◽  
Cell Membranes ◽  
White Muscle ◽  
Extracellular Ph ◽  
Posterior Portion ◽  
Arterial Inflow ◽  
Muscle Cell Membrane

Manipulations of pH and electrical gradients in a perfused preparation were used to analyze the factors controlling ammonia distribution and flux in trout white muscle after exercise. Trout were exercised to exhaustion, and then an isolated-perfused white muscle preparation with discrete arterial inflow and venous outflow was made from the posterior portion of the tail. The tail-trunks were perfused with low (7.4)-, medium (7.9)-, and high (8.4)-pH saline, achieved by varying HCO3- concentration ([HCO3-]) at constant Pco2. Intracellular and extracellular pH, ammonia, CO2, K+, Na+, and Cl- were measured. Muscle intracellular pH was not affected by changes in extracellular pH. Increasing extracellular pH caused a decrease in the transmembrane NH3 partial pressure (PNH3) gradient and a decrease in ammonia efflux. When extracellular K+ concentration was increased from 3.5 to 15 mM in the medium-pH group, a depolarization of the muscle cell membrane potential from -92 to -60 mV and a 0.1-unit depression in intracellular pH occurred. Ammonia efflux increased despite a marked reduction in the PNH3 gradient. Amiloride (10(-4) M) had no effect, indicating that Na+/H(+)-NH4+ exchange does not participate in ammonia transport in this system. A comparison of observed intracellular-to-extracellular ammonia distribution ratios with those modeled according to either pH or Nernst potential distributions supports a model in which ammonia distribution across white muscle cell membranes is affected by both pH and electrical gradients, indicating that the membranes are permeable to both NH3 and NH4+. Membrane potential, acting to retain high levels of NH4+ in the intracellular compartment, appears to have the dominant influence during the postexercise period. However, at rest, the pH gradient may be more important, resulting in much lower intracellular ammonia levels and distribution ratios. We speculate that the muscle cell membrane NH3-to-NH4+ permeability ratio in trout may change between the rest and postexercise condition.

A small synthetic molecule forms selective potassium channels to regulate cell membrane potential and blood vessel tone

2014 ◽  
Vol 12 (41) ◽  
pp. 8174-8179 ◽  
Author(s):  
Hui-Yan Zha ◽  
Bing Shen ◽  
Kwok-Hei Yau ◽  
Shing-To Li ◽  
Xiao-Qiang Yao ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Potassium Channels ◽  
Cell Membrane ◽  
Blood Vessel ◽  
Muscle Cell ◽  
Cell Membrane Potential ◽  
Vascular Muscle ◽  
Selective Channel ◽  
Synthetic Molecule ◽  
Muscle Cell Membrane

A molecule forms a K+-selective channel in the cell membrane to regulate vascular muscle cell membrane potential and blood vessel tone.

scholarly journals The UNC-112 Gene in Caenorhabditis elegansEncodes a Novel Component of Cell–Matrix Adhesion Structures Required for Integrin Localization in the Muscle Cell Membrane

2000 ◽  
Vol 150 (1) ◽  
pp. 253-264 ◽  
Author(s):  
Teresa M. Rogalski ◽  
Gregory P. Mullen ◽  
Mary M. Gilbert ◽  
Benjamin D. Williams ◽  
Donald G. Moerman
Keyword(s):  
Cell Membrane ◽  
Muscle Cell ◽  
Body Wall ◽  
Dense Body ◽  
The Body ◽  
Body Wall Muscle ◽  
Matrix Adhesion ◽  
Cell Matrix ◽  
Cell Matrix Adhesion ◽  
Muscle Cell Membrane

Embryos homozygous for mutations in the unc-52, pat-2, pat-3, and unc-112 genes of C. elegans exhibit a similar Pat phenotype. Myosin and actin are not organized into sarcomeres in the body wall muscle cells of these mutants, and dense body and M-line components fail to assemble. The unc-52 (perlecan), pat-2 (α-integrin), and pat-3 (β-integrin) genes encode ECM or transmembrane proteins found at the cell–matrix adhesion sites of both dense bodies and M-lines. This study describes the identification of the unc-112 gene product, a novel, membrane-associated, intracellular protein that colocalizes with integrin at cell–matrix adhesion complexes. The 720–amino acid UNC-112 protein is homologous to Mig-2, a human protein of unknown function. These two proteins share a region of homology with talin and members of the FERM superfamily of proteins. We have determined that a functional UNC-112::GFP fusion protein colocalizes with PAT-3/β-integrin in both adult and embryonic body wall muscle. We also have determined that UNC-112 is required to organize PAT-3/β-integrin after it is integrated into the basal cell membrane, but is not required to organize UNC-52/perlecan in the basement membrane, nor for DEB-1/vinculin to localize with PAT-3/β-integrin. Furthermore, UNC-112 requires the presence of UNC-52/perlecan and PAT-3/β-integrin, but not DEB-1/vinculin to become localized to the muscle cell membrane.

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