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Disparate effects of monensin and colchicine on intracellular processing of secretory proteins in culture rat hepatocytes.
- Source :
- European Journal of Biochemistry; 9/15/83, Vol. 135 Issue 2, p209-216, 8p
- Publication Year :
- 1983
-
Abstract
- We have studied the biosynthesis and intracellular processing of three major secretory proteins, albumin, α<subscript>1</subscript>-protease inhibitor and α<subscript>2u</subscript>-globulin, in cultured rat hepatocytes. The effect of secretion-blocking agents, monensin, a monovalent ionophore, and the microtubule-affecting agents colchicine and taxol was determined. In the control cells, α<subscript>1</subscript>-protease inhibitor, a glycoprotein, was first synthesized as an endoglycosidase-H-sensitive form with M<subscript>r</subscript> 51000, and then processed to two endoglycosidase-H-resistant forms having M<subscript>r</subscript> 51000 and 56000, the latter of which was secreted into the medium. Initially synthesized proalbumin was converted with chase to serum-type albumin, while no pro-type precursor was identified for α<subscript>2u</subscript>-globulin. In the cells lrcated with colchicine or taxol, in which secretion was greatly inhibited, the fully processed α<subscript>1</subscript>-protease inhibitor and albumin accumulated and were finally secreted into the medium. In the monensin-treated cells, however, most of the newly synthesized α<subscript>1</subscript>-protease inhibitor and albumin were not processed to the final mature forms, resulting in accumulation of two 51000-M<subscript>r</subscript> forms and proalbumin, respectively. Moreover in treated cells, proalbumin and the endoglycosidase-H-resistant α<subscript>1</subscript>-protease inhibitor were finally secreted into the medium. Such an effect was not caused by NH<subscript>4</subscript>Cl which also inhibited the secretion and is known to exert the similar effect as monensin on the receptor-mediated endocytosis pathway. Based on these results, the use of monensin may prove valuable for more detailed analysis of intracellular processing of various proteins. [ABSTRACT FROM AUTHOR]
- Subjects :
- BIOSYNTHESIS
PROTEINS
ALBUMINS
LIVER cells
COLCHICINE
PACLITAXEL
GLYCOPROTEINS
Subjects
Details
- Language :
- English
- ISSN :
- 00142956
- Volume :
- 135
- Issue :
- 2
- Database :
- Complementary Index
- Journal :
- European Journal of Biochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 13719050
- Full Text :
- https://doi.org/10.1111/j.1432-1033.1983.tb07639.x