On the effects of cycloheximide on cell motility and polarisation in Dictyostelium discoideum.
BACKGROUND
Cycloheximide is a protein synthesis inhibitor that acts specifically on the 60S subunit of eukaryotic ribosomes. It has previously been shown that a short incubation of Dictyostelium discoideum amoebae in cycloheximide eliminates fluid phase endocytosis.


RESULTS
We found that treatment with cycloheximide also causes the amoebae to retract their pseudopodia, round up and cease movement. Furthermore, fluid phase endocytosis, phagocytosis and capping cease in the presence of 2 mM cycloheximide, although membrane uptake, as measured using FM1-43, is unaffected. In the presence of cycloheximide, aggregation-competent amoebae sensitive to cAMP, although round, can still localise CRAC, ABP120, PI3K and actin polymerisation in response to a micropipette filled with cAMP. The behaviour of wild-type amoebae in the presence of cycloheximide is surprisingly similar to that of amoebae having a temperature-sensitive version of NSF at the restrictive temperature.


CONCLUSIONS
Our results may suggest that, upon cycloheximide treatment, either a labile protein required for polarised membrane recycling is lost, or a control mechanism linking protein synthesis to membrane recycling is activated.
Clotworthy
Margaret
M
MRC Laboratory of Molecular Biology, Hills Road, Cambridge, CB2 2QH, England. clotworm@mrc-lmb.cam.ac.uk
Traynor
David
D
D000199:Actins / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D001704:Biopolymers / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects*; D016764:Cell Polarity / Q000187:drug effects*; D003513:Cycloheximide / Q000494:pharmacology*; D004023:Dictyostelium / Q000166:cytology* / Q000187:drug effects*; D010587:Phagocytosis / Q000187:drug effects; D014176:Protein Biosynthesis; D013997:Time Factors
D000199:Actins; D001704:Biopolymers; D003513:Cycloheximide