Binding of Insulin to a Muscle Cell Membrane Preparation

Nature ◽  
1963 ◽  
Vol 197 (4870) ◽  
pp. 878-880 ◽  
Author(s):  
P. M. EDELMAN ◽  
S. L. ROSENTHAL ◽  
I. L. SCHWARTZ
Keyword(s):  
Cell Membrane ◽  
Muscle Cell ◽  
Membrane Preparation ◽  
Cell Membrane Preparation ◽  
Muscle Cell Membrane

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

Processing of surfactant protein B proprotein by a cathepsin D-like protease

1992 ◽  
Vol 263 (1) ◽  
pp. L95-L103 ◽  
Author(s):  
T. E. Weaver ◽  
S. Lin ◽  
B. Bogucki ◽  
C. Dey
Keyword(s):  
Epithelial Cell ◽  
Cell Membrane ◽  
Cathepsin D ◽  
Surfactant Protein ◽  
Membrane Preparation ◽  
Aspartyl Protease ◽  
Type Ii ◽  
Surfactant Protein B ◽  
Type Ii Cell ◽  
Cell Membrane Preparation

Surfactant protein B (SP-B) is a hydrophobic peptide of relative molecular weight (M(r)) = 8,000 that is associated with pulmonary surfactant phospholipids. SP-B is synthesized by the alveolar type II epithelial cell as a proprotein of M(r) = 42,000 which requires at least two proteolytic cleavages to generate the 79 residue mature SP-B peptide. We have previously reported that cleavage of the NH2-terminal propeptide, to generate a processing intermediate of M(r) = 25,000, occurs in close temporal approximation to secretion. In the present study we demonstrate that SP-B proprotein, isolated from stably transfected Chinese hamster ovary cells, is processed to M(r) = 25,000 by a crude type II cell membrane fraction but not by intact type II cells or type II cell conditioned media. In vitro processing of the proprotein by the type II cell membrane preparation resulted in release of a single peptide of M(r) = 16,000–17,000, which was detected by antiserum directed against antigenic epitopes in propeptide of the precursor. SP-B processing activity was extracted by Na2CO3 lysis of the type II cell membrane preparation, had a pH optimum of 5.0–6.0, and was inhibited by 10(-7) M pepstatin A, suggesting that the NH2-terminal peptide of the precursor is cleaved by an aspartyl protease. Consistent with this hypothesis, processing of SP-B by a crude type II cell membrane preparation was blocked by antiserum directed against the aspartyl protease cathepsin D; further, purified cathepsin D efficiently processed the SP-B precursor to M(r) = 25,000. Collectively these results suggest that cleavage of the NH2-terminal propeptide of the SP-B precursor is mediated by cathepsin D or a cathepsin D-like protease localized within the secretory pathway of the type II epithelial cell.

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.

Voltage-gated K+ channels at an early stage of chronic hypoxia-induced pulmonary hypertension in newborn piglets

2006 ◽  
Vol 291 (6) ◽  
pp. L1169-L1176 ◽  
Author(s):  
Candice D. Fike ◽  
Mark R. Kaplowitz ◽  
Yongmei Zhang ◽  
Jane A. Madden
Keyword(s):  
Pulmonary Hypertension ◽  
Smooth Muscle ◽  
Cell Membrane ◽  
Smooth Muscle Cell ◽  
Muscle Cell ◽  
Chronic Hypoxia ◽  
Early Stage ◽  
Membrane Properties ◽  
Voltage Gated ◽  
Muscle Cell Membrane

Our purpose was to determine whether smooth muscle cell membrane properties are altered in small pulmonary arteries (SPA) of piglets at an early stage of pulmonary hypertension. Piglets were raised in either room air (control) or hypoxia for 3 days. A microelectrode technique was used to measure smooth muscle cell membrane potential ( Em) in cannulated, pressurized SPA (100- to 300-μm diameter). SPA responses to the voltage-gated K+ (KV) channel antagonist 4-aminopyridine (4-AP) and the KV1 family channel antagonist correolide were measured. Other SPA were used to assess amounts of KV1.2, KV1.5, and KV2.1 (immunoblot technique). Em was more positive in SPA of chronically hypoxic piglets than in SPA of comparable-age control piglets. The magnitude of constriction elicited by either 4-AP or correolide was diminished in SPA from hypoxic piglets. Abundances of KV1.2 were reduced, whereas abundances of both KV1.5 and KV2.1 were unaltered, in SPA from hypoxic piglets. At least partly because of reduced amounts of KV1.2, smooth muscle cell membrane properties are altered such that Em is depolarized and KV channel family function is impaired in SPA of piglets at an early stage of chronic hypoxia-induced pulmonary hypertension.

scholarly journals Receptor-Based Differences in Human Aortic Smooth Muscle Cell Membrane Stiffness

Hypertension ◽  
2001 ◽  
Vol 38 (5) ◽  
pp. 1158-1161 ◽  
Author(s):  
Hayden Huang ◽  
Roger D. Kamm ◽  
Peter T.C. So ◽  
Richard T. Lee
Keyword(s):  
Smooth Muscle ◽  
Cell Membrane ◽  
Smooth Muscle Cell ◽  
Muscle Cell ◽  
Aortic Smooth Muscle Cell ◽  
Aortic Smooth Muscle ◽  
Membrane Stiffness ◽  
Muscle Cell Membrane
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