Abstract
To investigate the intracellular processing of endothelin-1 (ET-1), the synthesis and secretion of preproET-1 (PPET-1) was studied in transiently transfected COS-7 cells. Replacements at the highly conserved C-terminal region of ET-1 were made by site-directed mutagenesis, with codons for residues Ile-20 and Trp-21 being replaced by one for Ala in the PPET-1 cDNA. The mutant and wildtype PPET-1 cDNAs were expressed in COS-7 cells following transient transfection, and cell media and extracts, collected after 48 h, were assayed for ET-1 and big ET-1 by radioimmunoassay. The concentration of immunoreactive ET-1 in the medium obtained from the Ala-21-ET-1 mutant was 10-fold lower than that from PPET-1 wildtype and (Ala-20-ET-1) PPET-1 transfected cells. Moreover, Ala-21 -big ET-1 accumulated in the cells transfected with the cDNA for (Ala-21-ET-1) PPET-1, whereas there was no significant accumulation of ET-1-like or big ET-1-like immunoreactivity in the cells transfected with cDNAs for PPET-1 wildtype and (Ala-20-ET-1) PPET-1. These results suggest that Trp-21 is involved in intracellular processing and secretion of big ET-1.
Original language | English (US) |
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Pages (from-to) | 89-94 |
Number of pages | 6 |
Journal | Molecular and Cellular Endocrinology |
Volume | 110 |
Issue number | 1-2 |
DOIs | |
State | Published - Apr 28 1995 |
Externally published | Yes |
Keywords
- Big endothelin-1
- Endothelin-1
- Preproendothelin-1
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Endocrinology