Fate of injected 125I-labeled cholera toxin taken up by rat liver in vivo. Generation of the active A1 peptide in the endosomal compartment - PubMed (original) (raw)
Fate of injected 125I-labeled cholera toxin taken up by rat liver in vivo. Generation of the active A1 peptide in the endosomal compartment
M Janicot et al. Eur J Biochem. 1987.
Free article
Abstract
Subcellular fractionation techniques have been used to assess the localization of injected 125I-labeled cholera toxin (125I-CT) taken up by rat liver in vivo, and to determine whether internalization of the toxin is required for the generation of the active A1 peptide. The uptake of injected 125I-CT into the liver is maximal at 5 min (about 10% injected dose/g). At this time the radioactivity is for the most part recovered in the microsomal (P) fraction, but later on it progressively associates with the mitochondrial-lysosomal (ML) and supernatant fractions. The radioactivity is enriched 7-fold in plasma membranes at 5-15 min, and 15-60-fold in Golgi-endosome (GE) fractions at 15-60 min. On analytical sucrose gradients the radioactivity associated with the P fraction is progressively displaced from the region of 5'-nucleotidase (a plasma membrane marker) to that of galactosyltransferase (a Golgi marker). On Percoll gradients, however, it is displaced towards acid phosphatase (a lysosomal marker). Density-shift experiments, using Triton WR 1339, suggest that some radioactivity associated with the P fraction (at 30 min) and all the radioactivity present in the ML fraction (at 2 h) is intrinsic to acid-phosphatase-containing structures, presumably lysosomes. Comparable experiments using 3,3'-diaminobenzidine cytochemistry indicate that the radioactivity present in GE fractions is separable from galactosyltransferase, and thus is presumably associated with endosomes. The fate of injected 125I-labeled cholera toxin B subunit differs from that of the whole toxin by a more rapid uptake (and/or clearance) of the ligand into subcellular fractions, and a greater accumulation of ligand in the ML fraction. Analysis of GE fractions by SDS/polyacrylamide gel electrophoresis shows that, up to 10 min after injection of 125I-CT, about 80% of the radioactivity is recovered as A subunit and 20% as B subunit, similarly to control toxin. Later on there is a time-dependent decrease in the amount of A subunit and, at least with the intermediate GE fraction, a concomitant appearance of A1 peptide (about 15% of the total at 60 min). In contrast the radioactivity associated with plasma membranes remains indistinguishable from unused toxin. It is concluded that, upon interaction with hepatocytes, 125I-CT (both subunits A and B) sequentially associates with plasma membranes, endosomes and lysosomes, and that endosomes may represent the major subcellular site at which the A1 peptide is generated.
Similar articles
- Fate of injected glucagon taken up by rat liver in vivo. Degradation of internalized ligand in the endosomal compartment.
Authier F, Janicot M, Lederer F, Desbuquois B. Authier F, et al. Biochem J. 1990 Dec 15;272(3):703-12. doi: 10.1042/bj2720703. Biochem J. 1990. PMID: 2268296 Free PMC article. - Fate of injected human growth hormone in the female rat liver in vivo.
Postel-Vinay MC, Kayser C, Desbuquois B. Postel-Vinay MC, et al. Endocrinology. 1982 Jul;111(1):244-51. doi: 10.1210/endo-111-1-244. Endocrinology. 1982. PMID: 7084113 - Uptake of injected 125I-ricin by rat liver in vivo. Subcellular distribution and characterization of the internalized ligand.
Frénoy JP, Turpin E, Janicot M, Gehin-Fouque F, Desbuquois B. Frénoy JP, et al. Biochem J. 1992 May 15;284 ( Pt 1)(Pt 1):249-57. doi: 10.1042/bj2840249. Biochem J. 1992. PMID: 1599402 Free PMC article. - The subcellular biochemistry of thyroid.
Hilderson HJ, Van Dessel G, Lagrou A, Dierick W. Hilderson HJ, et al. Subcell Biochem. 1980;7:213-65. doi: 10.1007/978-1-4615-7948-9_5. Subcell Biochem. 1980. PMID: 7003823 Review.
Cited by
- KDEL receptor (Erd2p)-mediated retrograde transport of the cholera toxin A subunit from the Golgi involves COPI, p23, and the COOH terminus of Erd2p.
Majoul I, Sohn K, Wieland FT, Pepperkok R, Pizza M, Hillemann J, Söling HD. Majoul I, et al. J Cell Biol. 1998 Nov 2;143(3):601-12. doi: 10.1083/jcb.143.3.601. J Cell Biol. 1998. PMID: 9813083 Free PMC article. - Transport of an external Lys-Asp-Glu-Leu (KDEL) protein from the plasma membrane to the endoplasmic reticulum: studies with cholera toxin in Vero cells.
Majoul IV, Bastiaens PI, Söling HD. Majoul IV, et al. J Cell Biol. 1996 May;133(4):777-89. doi: 10.1083/jcb.133.4.777. J Cell Biol. 1996. PMID: 8666663 Free PMC article. - Inhibition of heat-labile cholera and Escherichia coli enterotoxins by brefeldin A.
Donta ST, Beristain S, Tomicic TK. Donta ST, et al. Infect Immun. 1993 Aug;61(8):3282-6. doi: 10.1128/iai.61.8.3282-3286.1993. Infect Immun. 1993. PMID: 8392970 Free PMC article. - Interactions of cholera toxin with isolated hepatocytes. Effects of low pH, chloroquine and monensin on toxin internalization, processing and action.
Janicot M, Clot JP, Desbuquois B. Janicot M, et al. Biochem J. 1988 Aug 1;253(3):735-43. doi: 10.1042/bj2530735. Biochem J. 1988. PMID: 2845931 Free PMC article. - Fate of injected glucagon taken up by rat liver in vivo. Degradation of internalized ligand in the endosomal compartment.
Authier F, Janicot M, Lederer F, Desbuquois B. Authier F, et al. Biochem J. 1990 Dec 15;272(3):703-12. doi: 10.1042/bj2720703. Biochem J. 1990. PMID: 2268296 Free PMC article.
MeSH terms
Substances
LinkOut - more resources
Full Text Sources
Research Materials