TY - JOUR
T1 - Constitutive lysosomal targeting and degradation of bovine endothelin- converting enzyme-1a mediated by novel signals in its alternatively spliced cytoplasmic tail
AU - Emoto, Noriaki
AU - Nurhantari, Yudha
AU - Alimsardjono, Haryanto
AU - Xie, Jian
AU - Yamada, Takahisa
AU - Yanagisawa, Masashi
AU - Matsuo, Masafumi
N1 - Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.
PY - 1999/1/15
Y1 - 1999/1/15
N2 - Endothelin-converting enzyme-1 (ECE-1) is a type II membrane protein that catalyzes the proteolytic activation of big endothelin-1 to endothelin- 1 (ET-1). The subcellular distribution of ECE-1, and hence the exact site of physiological activation of big ET-1, remains controversial. Here, we demonstrate with several complementary methods that the two alternatively spliced bovine ECE-1 isoforms, ECE-1a and ECE-1b, differing only in the first 30 amino acids of their N-terminal cytoplasmic tails, exhibit strikingly distinct intracellular sorting patterns. Bovine ECE-1a, which is responsible for the intracellular cleavage of big ET-1 in endothelial cells, is constitutively recruited into the lysosome, where it is rapidly degraded. In contrast, bovine ECE-1b, the isoform found in cultured smooth muscle cells, is transported to the plasma membrane by a default pathway and functions as an ectoenzyme. Mutational analyses reveal that the N-terminal tip of the cytoplasmic domain of bovine ECE-1a contains novel proline-containing signals that mediate constitutive lysosomal targeting. Analyses of chimeric ECE- 1/transferrin receptors demonstrate that the cytoplasmic tail of bovine ECE- 1a is sufficient for the lysosomal delivery and rapid degradation. Our results suggest that the distinct intracellular targeting of bovine ECE-1 isoforms may provide new insights into functional aspect of the endothelin system and that the cell permeability of ECE inhibitor compounds should be carefully considered during their pharmacological development.
AB - Endothelin-converting enzyme-1 (ECE-1) is a type II membrane protein that catalyzes the proteolytic activation of big endothelin-1 to endothelin- 1 (ET-1). The subcellular distribution of ECE-1, and hence the exact site of physiological activation of big ET-1, remains controversial. Here, we demonstrate with several complementary methods that the two alternatively spliced bovine ECE-1 isoforms, ECE-1a and ECE-1b, differing only in the first 30 amino acids of their N-terminal cytoplasmic tails, exhibit strikingly distinct intracellular sorting patterns. Bovine ECE-1a, which is responsible for the intracellular cleavage of big ET-1 in endothelial cells, is constitutively recruited into the lysosome, where it is rapidly degraded. In contrast, bovine ECE-1b, the isoform found in cultured smooth muscle cells, is transported to the plasma membrane by a default pathway and functions as an ectoenzyme. Mutational analyses reveal that the N-terminal tip of the cytoplasmic domain of bovine ECE-1a contains novel proline-containing signals that mediate constitutive lysosomal targeting. Analyses of chimeric ECE- 1/transferrin receptors demonstrate that the cytoplasmic tail of bovine ECE- 1a is sufficient for the lysosomal delivery and rapid degradation. Our results suggest that the distinct intracellular targeting of bovine ECE-1 isoforms may provide new insights into functional aspect of the endothelin system and that the cell permeability of ECE inhibitor compounds should be carefully considered during their pharmacological development.
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U2 - 10.1074/jbc.274.3.1509
DO - 10.1074/jbc.274.3.1509
M3 - Article
C2 - 9880527
AN - SCOPUS:0033556165
SN - 0021-9258
VL - 274
SP - 1509
EP - 1518
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 3
ER -