Nuclear localization of endothelin-converting enzyme-1: subisoform specificity.
OBJECTIVE
The biosynthesis of endothelin-1 (ET-1), the most potent vasoconstrictor with mitogenic properties, involves the processing of intermediate protein big ET-1 by a unique metalloprotease, endothelin-converting enzyme-1 (ECE-1). ECE-1 has 4 subisoforms that possess the same catalytic properties but different localization patterns on the plasma membrane and cytosol. We investigated the trafficking of ECE-1 subisoforms using green fluorescent protein-tagged recombinant enzymes in target and nontarget cells.


RESULTS
ECE-1 localization was studied using confocal microscopy, which provides evidence for the first time that both ET-1 and ECE-1a are also found in the nuclear compartment in transiently transfected cells as well as in native endothelial cells that endogenously possess the ET system. In cells maintained in high-glucose medium, ECE-1a-specific staining shifted from plasma membrane to intracellular compartments. ECE-1b subisoform, however, is mainly in the cytosolic compartment, indicating a subisoform specificity for nuclear localization.


CONCLUSIONS
Our findings define a novel localization pattern for the ET system, which may be differentially regulated under pathophysiological conditions.
Jafri
Farahdiba
F
Clinical and Experimental Therapeutics Program, University of Georgia and Vascular Biology Center, Medical College of Georgia, Augusta, GA 30912, USA.
Ergul
Adviye
A
D000818:Animals; D016466:CHO Cells; D002196:Capillaries / Q000166:cytology / Q000201:enzymology; D002460:Cell Line; D002467:Cell Nucleus / Q000201:enzymology*; D006224:Cricetinae; D003412:Cricetulus; D016232:Endothelins / Q000378:metabolism; D004730:Endothelium, Vascular / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics; D049452:Green Fluorescent Proteins; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D008164:Luminescent Proteins / Q000096:biosynthesis / Q000235:genetics; D008666:Metalloendopeptidases / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D013379:Substrate Specificity; D014162:Transfection
D016232:Endothelins; D007527:Isoenzymes; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; C492359:ECEL1 protein, human; D008666:Metalloendopeptidases