Metallopeptidase inhibitors induce an up-regulation of endothelin-converting enzyme levels and its redistribution from the plasma membrane to an intracellular compartment.
Endothelin-converting enzyme is a phosphoramidon-sensitive membrane metallopeptidase that catalyses the final step in biosynthesis of the potent vasoactive endothelin peptides. Immunomagnetic separation technology and immunohistochemistry have been used to demonstrate the co-localisation of endothelin-converting enzyme with the established ectoenzyme, aminopeptidase N, on the surface of endothelial cells. Unlike aminopeptidase N, however, endothelin-converting enzyme is seen to associate in clusters on the plasma membrane which can be distinguished from caveolae both biochemically and immunologically. Pre-treatment of endothelial cells with the metallopeptidase inhibitors phosphoramidon or thiorphan in the range 0.01-100 microM produced a dose-dependent increase in the levels of endothelin-converting enzyme protein and its accumulation in an intracellular compartment. No corresponding change in the levels of endothelin-converting enzyme-1 mRNA was detected under these conditions, nor in the levels of the closely related metalloenzyme, endopeptidase-24.11. The phosphoramidon and thiorphan-dependent increase is not due to direct inhibition of endothelin-converting enzyme not endopeptidase-24.11 but, rather, to an inhibition of the selective turnover of endothelin-converting enzyme protein.
Barnes
K
K
Department of Biochemistry and Molecular Biology, University of Leeds, UK.
Shimada
K
K
Takahashi
M
M
Tanzawa
K
K
Turner
A J
AJ
D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D001483:Base Sequence; D002451:Cell Compartmentation; D002462:Cell Membrane / Q000201:enzymology; D002478:Cells, Cultured; D000072396:Endothelin-Converting Enzymes; D005455:Fluorescent Antibody Technique; D006020:Glycopeptides / Q000494:pharmacology; D015151:Immunoblotting; D018189:Immunomagnetic Separation; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors*; D008969:Molecular Sequence Data; D011480:Protease Inhibitors / Q000494:pharmacology*; D013552:Swine; D015244:Thiorphan / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects
D006020:Glycopeptides; D011480:Protease Inhibitors; D015244:Thiorphan; D016282:Aspartic Acid Endopeptidases; D008666:Metalloendopeptidases; D000072396:Endothelin-Converting Enzymes; C008890:phosphoramidon