Transport of apically but not basolaterally internalized ricin to the Golgi apparatus is stimulated by 8-Br-cAMP in MDCK cells.
The plant toxin ricin has to be transported to the Golgi apparatus after endocytosis to exert its toxic effect. In this study we show that transport of apically endocytosed ricin to the Golgi apparatus is stimulated by 8-Br-cAMP in polarized MDCK cells. This stimulation is counteracted by the PKA inhibitor H-89. In contrast, there is no increase in the transport to the Golgi apparatus of ricin internalized from the basolateral membrane. These results suggest that protein kinase A selectively regulates endosome to Golgi transport in these cells.
Institute for Cancer Research, The Norwegian Radium Hospital, Oslo, Norway.
A
A
Llorente
B
B
van Deurs
K
K
Sandvig
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004285:Dogs; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism; D004789:Enzyme Activation; D006056:Golgi Apparatus / Q000378:metabolism*; D012276:Ricin / Q000378:metabolism*
D015124:8-Bromo Cyclic Adenosine Monophosphate; D012276:Ricin; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases