Pathways followed by ricin and Shiga toxin into cells.
The plant toxin ricin and the bacterial toxin Shiga toxin belong to a group of protein toxins that inhibit protein synthesis in cells enzymatically after entry into the cytosol. Ricin and Shiga toxin, which both have an enzymatically active moiety that inactivates ribosomes and a moiety that binds to cell surface receptors, enter the cytosol after binding to the cell surface, endocytosis by different mechanisms, and retrograde transport to the Golgi apparatus and the endoplasmic reticulum (ER). The toxins can be used to investigate the various transport steps involved, both the endocytic mechanisms as well as pathways for retrograde transport to the ER. Recent studies show that not only do several endocytic mechanisms exist in the same cell, but they are not equally sensitive to removal of cholesterol. New data have revealed that there is also more than one pathway leading from endosomes to the Golgi apparatus and retrogradely from the Golgi to the ER. Trafficking of protein toxins along these pathways will be discussed in the present article.
Sandvig
Kirsten
K
Institute for Cancer Research, The Norwegian Radium Hospital, Montebello, 0310 Oslo, Norway. ksandvig@radium.uio.no
Grimmer
Stine
S
Lauvrak
Silje Ugland
SU
Torgersen
Maria Lyngaas
ML
Skretting
Grethe
G
van Deurs
Bo
B
Iversen
Tore Geir
TG
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D021941:Caveolae / Q000378:metabolism; D004705:Endocytosis / Q000187:drug effects; D004721:Endoplasmic Reticulum / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism; D005057:Eukaryotic Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D006801:Humans; D008954:Models, Biological; D012276:Ricin / Q000378:metabolism*; D022621:Shiga Toxin / Q000378:metabolism*
D016244:Guanosine 5'-O-(3-Thiotriphosphate); D022621:Shiga Toxin; D012276:Ricin