Characterization of the calpastatin defect in erythrocytes from patients with essential hypertension.
In erythrocytes of patients with essential hypertension the level of calpastatin activity was found to be significantly lower than in red cells of normotensive subjects (1). We now demonstrate, by Western blot analysis, that the decreased inhibitory activity is due to a corresponding decrease in the amount of the inhibitor protein. This is also supported by the observation that calpastatins isolated and purified from erythrocytes of normotensive and hypertensive patients, have identical specific activity. Data are presented indicating that the decreased level of calpastatin cannot be ascribed to an accelerated decay of the inhibitor during the erythrocyte life span. Taken together the previous and present results further emphasize that an umbalanced proteolytic system may represent one of the molecular mechanisms responsible for those membrane abnormalities underlying the development of essential hypertension and its clinical complications.
Pontremoli
S
S
Institute of Biological Chemistry, University of Genoa, Italy.
Salamino
F
F
Sparatore
B
B
De Tullio
R
R
Pontremoli
R
R
Melloni
E
E
D000911:Antibodies, Monoclonal; D015153:Blotting, Western; D002135:Calcium-Binding Proteins / Q000097:blood*; D002154:Calpain / Q000037:antagonists & inhibitors; D003600:Cytosol / Q000378:metabolism; D004905:Erythrocyte Aging; D004910:Erythrocyte Membrane / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism*; D006801:Humans; D006973:Hypertension / Q000097:blood*; D011480:Protease Inhibitors
D000911:Antibodies, Monoclonal; D002135:Calcium-Binding Proteins; D011480:Protease Inhibitors; C033668:calpastatin; D002154:Calpain