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Internalization of cholera toxin by different endocytic mechanisms.
J Cell Sci. 2001 Oct; 114(Pt 20):3737-47.JC

Abstract

The mechanism of cholera toxin (CT) internalization has been investigated using Caco-2 cells transfected with caveolin to induce formation of caveolae, HeLa cells with inducible synthesis of mutant dynamin (K44A) and BHK cells in which antisense mRNA to clathrin heavy chain can be induced. Here we show that endocytosis and the ability of CT to increase the level of cAMP were unaltered in caveolin-transfected cells grown either in a non-polarized or polarized manner. Treatment of Caco-2 cells with filipin reduced CT-uptake by less than 20%, suggesting that caveolae do not play a major role in the uptake. Extraction of cholesterol by methyl-beta-cyclodextrin, which removes caveolae and inhibits uptake from clathrin-coated pits, gave 30-40% reduction of CT-endocytosis. Also, CT-uptake in HeLa K44A cells was reduced by 50-70% after induction of mutant dynamin, which inhibits both caveolae- and clathrin-dependent endocytosis. These cells contain few caveolae, and nystatin and filipin had no effect on CT-uptake, indicating major involvement of clathrin-coated pits in CT-internalization. Similarly, in BHK cells, where clathrin-dependent endocytosis is blocked by induction of antisense clathrin heavy chain, the CT-uptake was reduced by 50% in induced cells. In conclusion, a large fraction of CT can be endocytosed by clathrin-dependent as well as by caveolae- and clathrin-independent endocytosis in different cell types.

Authors+Show Affiliations

Institute for Cancer Research, the Norwegian Radium Hospital, Montebello, 0310 Oslo, Norway.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

11707525

Citation

Torgersen, M L., et al. "Internalization of Cholera Toxin By Different Endocytic Mechanisms." Journal of Cell Science, vol. 114, no. Pt 20, 2001, pp. 3737-47.
Torgersen ML, Skretting G, van Deurs B, et al. Internalization of cholera toxin by different endocytic mechanisms. J Cell Sci. 2001;114(Pt 20):3737-47.
Torgersen, M. L., Skretting, G., van Deurs, B., & Sandvig, K. (2001). Internalization of cholera toxin by different endocytic mechanisms. Journal of Cell Science, 114(Pt 20), 3737-47.
Torgersen ML, et al. Internalization of Cholera Toxin By Different Endocytic Mechanisms. J Cell Sci. 2001;114(Pt 20):3737-47. PubMed PMID: 11707525.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Internalization of cholera toxin by different endocytic mechanisms. AU - Torgersen,M L, AU - Skretting,G, AU - van Deurs,B, AU - Sandvig,K, PY - 2001/11/15/pubmed PY - 2002/3/7/medline PY - 2001/11/15/entrez SP - 3737 EP - 47 JF - Journal of cell science JO - J. Cell. Sci. VL - 114 IS - Pt 20 N2 - The mechanism of cholera toxin (CT) internalization has been investigated using Caco-2 cells transfected with caveolin to induce formation of caveolae, HeLa cells with inducible synthesis of mutant dynamin (K44A) and BHK cells in which antisense mRNA to clathrin heavy chain can be induced. Here we show that endocytosis and the ability of CT to increase the level of cAMP were unaltered in caveolin-transfected cells grown either in a non-polarized or polarized manner. Treatment of Caco-2 cells with filipin reduced CT-uptake by less than 20%, suggesting that caveolae do not play a major role in the uptake. Extraction of cholesterol by methyl-beta-cyclodextrin, which removes caveolae and inhibits uptake from clathrin-coated pits, gave 30-40% reduction of CT-endocytosis. Also, CT-uptake in HeLa K44A cells was reduced by 50-70% after induction of mutant dynamin, which inhibits both caveolae- and clathrin-dependent endocytosis. These cells contain few caveolae, and nystatin and filipin had no effect on CT-uptake, indicating major involvement of clathrin-coated pits in CT-internalization. Similarly, in BHK cells, where clathrin-dependent endocytosis is blocked by induction of antisense clathrin heavy chain, the CT-uptake was reduced by 50% in induced cells. In conclusion, a large fraction of CT can be endocytosed by clathrin-dependent as well as by caveolae- and clathrin-independent endocytosis in different cell types. SN - 0021-9533 UR - https://www.unboundmedicine.com/medline/citation/11707525/Internalization_of_cholera_toxin_by_different_endocytic_mechanisms_ L2 - http://jcs.biologists.org/cgi/pmidlookup?view=long&pmid=11707525 DB - PRIME DP - Unbound Medicine ER -