Stimulatory effect of vanadate on (Na+ + K+)-ATPase activity and on 3H-ouabain-binding in a cat heart cell membrane preparation

Nature ◽  
1979 ◽  
Vol 278 (5703) ◽  
pp. 459-461 ◽  
Author(s):  
ERLAND ERDMANN ◽  
WOLFGANG KRAWIETZ ◽  
GUNTHER PHILIPP ◽  
INGELORE HACKBARTH ◽  
WILHELM SCHMITZ ◽  
...  
Keyword(s):  
Cell Membrane ◽  
Atpase Activity ◽  
Membrane Preparation ◽  
Heart Cell ◽  
Ouabain Binding ◽  
Heart Cell Membrane ◽  
Cell Membrane Preparation ◽  
Cat Heart

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.

scholarly journals Identification of diphtheria toxin receptor and a nonproteinous diphtheria toxin-binding molecule in Vero cell membrane.

1988 ◽  
Vol 107 (2) ◽  
pp. 511-519 ◽  
Author(s):  
E Mekada ◽  
Y Okada ◽  
T Uchida
Keyword(s):  
Cell Membrane ◽  
Vero Cell ◽  
Diphtheria Toxin ◽  
Vero Cells ◽  
Binding Activity ◽  
Membrane Preparation ◽  
Toxin Binding ◽  
Surface Receptor ◽  
Toxin Receptor ◽  
Cell Membrane Preparation

Two substances possessing the ability to bind to diphtheria toxin (DT) were found to be present in a membrane fraction from DT-sensitive Vero cells. One of these substances was found on the basis of its ability to bind DT and inhibit its cytotoxic effect. This inhibitory substance competitively inhibited the binding of DT to Vero cells. However this inhibitor could not bind to CRM197, the product of a missense mutation in the DT gene, and did not inhibit the binding of CRM197 to Vero cells. Moreover, similar levels of the inhibitory activity were observed in membrane fractions from DT-insensitive mouse cells, suggesting the inhibitor is not the DT receptor which is specifically present in DT-sensitive cells. The second DT-binding substance was found in the same Vero cell membrane preparation by assaying the binding of 125I-labeled CRM197. Such DT-binding activity could not be observed in membrane preparation from mouse L cells. From competition studies using labeled DT and CRM proteins, we conclude that this binding activity is due to the surface receptor for DT. Treatment of these substances with several enzymes revealed that the inhibitor was sensitive to certain RNases but resistant to proteases, whereas the DT receptor was resistant to RNase but sensitive to proteases. The receptor was solubilized and partially purified by chromatography on CM-Sepharose column. Immunoprecipitation and Western blotting analysis of the partially purified receptor revealed that a 14.5-kD protein is the DT receptor, or at least a component of it.

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
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