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Endocytosis and intracellular localisation of type 1 ribosome-inactivating protein saporin-s6.
- Source :
-
Journal of biological regulators and homeostatic agents [J Biol Regul Homeost Agents] 2012 Jan-Mar; Vol. 26 (1), pp. 97-109. - Publication Year :
- 2012
-
Abstract
- Saporin-S6 is a single-chain ribosome-inactivating protein (RIP) that has low toxicity in cells and animals. When the protein is bound to a carrier that facilitates cellular uptake, the protein becomes highly and selectively toxic to the cellular target of the carrier. Thus, saporin-S6 is one of the most widely used RIPs in the preparation of immunoconjugates for anti-cancer therapy. The endocytosis of saporin-S6 by the neoplastic HeLa cells and the subsequent intracellular trafficking were investigated by confocal microscopy that utilises indirect immunofluorescence analysis and transmission electron microscopy that utilises a direct assay with gold-conjugated saporin-S6 and an indirect immunoelectron microscopy assay. Our results indicate that saporin-S6 was taken up by cells mainly through receptor-independent endocytosis. Confocal microscopy analysis showed around 30% co-localisation of saporin-S6 with the endosomal compartment and less than 10% co-localisation with the Golgi apparatus. The pathway identified by the immunofluorescence assay and transmission electron microscopy displayed a progressive accumulation of saporin-S6 in perinuclear vesicular structures. The main findings of this work are the following: i) the nuclear localisation of saporin-S6 and ii) the presence of DNA gaps resulting from abasic sites in HeLa nuclei after intoxication with saporin-S6.
- Subjects :
- DNA Damage
Endosomes metabolism
Fluorescent Antibody Technique, Indirect
Golgi Apparatus metabolism
HeLa Cells metabolism
Humans
Microscopy, Confocal
Microscopy, Electron, Transmission
Protein Synthesis Inhibitors pharmacokinetics
Ribosome Inactivating Proteins, Type 1 pharmacokinetics
Saporins
Endocytosis
Ribosome Inactivating Proteins, Type 1 metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0393-974X
- Volume :
- 26
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Journal of biological regulators and homeostatic agents
- Publication Type :
- Academic Journal
- Accession number :
- 22475101