Secretion of endothelin converting enzyme-1a: the hydrophobic signal anchor domain alone is not sufficient to promote membrane localization.
Endothelin converting enzyme-1 (ECE-1) is a type II membrane protein that is important for the proteolytic activation of big endothelin-1 to endothelin-1. Although the highly conserved zinc-binding motif is known to be located in the extracellular domain, the role(s) of the N-terminal and membrane-spanning signal anchor domains in the biosynthesis and function of ECE-1 isoforms, ECE-1a, ECE-1b, and ECE-1c, remain undetermined. In this study, we provide evidence that the deletion of the cytoplasmic N-terminal tail (residues 1-55) of ECE-1a results in the cleavage of a potential signal peptide located in the signal anchor domain leading to the partial secretion of the recombinant enzyme into the media. However, the truncation of N-terminal and/or signal anchor domain does not affect the activity of ECE-1a. Therefore, our results demonstrate that the hydrophobic signal anchor domain alone is not sufficient for the membrane anchoring of ECE-1a and that the N-terminal domain of ECE-1a is important for membrane targeting as well as the intracellular localization of the enzyme.
Department of Biochemistry and Molecular Biology, University of Georgia, Athens, USA.
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Brooks
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Fernandez
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Ergul
D000595:Amino Acid Sequence; D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016466:CHO Cells; D002462:Cell Membrane / Q000201:enzymology*; D006224:Cricetinae; D019332:Endothelin-1; D000072396:Endothelin-Converting Enzymes; D016232:Endothelins / Q000378:metabolism; D004792:Enzyme Precursors / Q000378:metabolism*; D007700:Kinetics; D008666:Metalloendopeptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D011498:Protein Precursors / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D021382:Protein Sorting Signals; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014162:Transfection
D019332:Endothelin-1; D016232:Endothelins; D004792:Enzyme Precursors; D011498:Protein Precursors; D021382:Protein Sorting Signals; D011993:Recombinant Fusion Proteins; D016282:Aspartic Acid Endopeptidases; D008666:Metalloendopeptidases; D000072396:Endothelin-Converting Enzymes