TY - JOUR
T1 - Specific inhibitors implicate a soluble metalloendoproteinase in exocytosis
AU - Mundy, Dorothy
AU - Hermann, Todd
AU - Strittmatter, Warren J.
N1 - Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.
PY - 1987/12
Y1 - 1987/12
N2 - 1. Previous studies have demonstrated that exocytosis in adrenal chromaffin cells appears to require zinc-dependent endoproteinase activity. 2. Chromaffin cells have metal-dependent endoproteinases in both the plasma membrane and the soluble fraction of homogenized cells. In order to further study critically the role of metalloproteinase in exocytosis, and prior to purification, we needed to determine which one of several adrenal metalloproteinases is implicated in exocytosis. 3. The studies described here demonstrate that the metal-dependent endoproteinases in these two subcellular fractions can be differentiated by selective inhibitors. In both intact and permeabilized cells, the plasma membrane metalloproteinase, but not the soluble proteinases, is inhibited by phosphoramidon. Phosphoramidon does not block exocytosis in either intact or permeabilized cells. 4. In addition, the plasma membrane metalloproteinase appears to have its catalytic site facing the outside of the cell. 5. Because of these observations the plasma membrane metalloproteinase does not appear to be required in exocytosis. Since soluble metalloproteinase activity is inhibited by proteinase inhibitors at concentrations which block exocytosis, a soluble, and not the plasma membrane, metalloproteinase appears to be required in exocytosis.
AB - 1. Previous studies have demonstrated that exocytosis in adrenal chromaffin cells appears to require zinc-dependent endoproteinase activity. 2. Chromaffin cells have metal-dependent endoproteinases in both the plasma membrane and the soluble fraction of homogenized cells. In order to further study critically the role of metalloproteinase in exocytosis, and prior to purification, we needed to determine which one of several adrenal metalloproteinases is implicated in exocytosis. 3. The studies described here demonstrate that the metal-dependent endoproteinases in these two subcellular fractions can be differentiated by selective inhibitors. In both intact and permeabilized cells, the plasma membrane metalloproteinase, but not the soluble proteinases, is inhibited by phosphoramidon. Phosphoramidon does not block exocytosis in either intact or permeabilized cells. 4. In addition, the plasma membrane metalloproteinase appears to have its catalytic site facing the outside of the cell. 5. Because of these observations the plasma membrane metalloproteinase does not appear to be required in exocytosis. Since soluble metalloproteinase activity is inhibited by proteinase inhibitors at concentrations which block exocytosis, a soluble, and not the plasma membrane, metalloproteinase appears to be required in exocytosis.
KW - adrenal chromaffin cells
KW - exocytosis
KW - metalloendoproteases
KW - proteinase inhibitors
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U2 - 10.1007/BF00733794
DO - 10.1007/BF00733794
M3 - Article
C2 - 3330469
AN - SCOPUS:0023614813
SN - 0272-4340
VL - 7
SP - 425
EP - 437
JO - Cellular and Molecular Neurobiology
JF - Cellular and Molecular Neurobiology
IS - 4
ER -