title: ADP-ribosylation of Rho-proteins with botulinum C3 exoenzyme inhibits invasion and shape changes of T-lymphoma cells.
abstract: C3 exoenzyme from Clostridium botulinum ADP-ribosylates the small GTP-binding protein Rho with a high specificity. The use of C3 has shown that Rho-mediated signaling is involved in the regulation of actin-dependent processes in various cell types. In order to investigate the role of Rho-proteins in lymphocyte crawling, we have analyzed the effects of C3 on a T-cell line derived from the murine BW5147 lymphoma. Pretreatment of the lymphoma cells with C3, in conditions where Rho was actually ADP-ribosylated, strongly inhibited the characteristic shape changes resulting from extension and retraction of pseudopodia. Concomitantly, invasion of the cells through a monolayer of fibroblast-like cells was also inhibited. C3-treatment did not affect the total F-actin content of the cells, as measured by flow cytometry of cells stained with phalloidin. Yet, microscopical observation revealed that the accumulations of F-actin, which were seen in the pseudopodia of untreated cells, were absent after treatment with C3. This suggests that C3 may affect actin polymerization locally. The inhibitory effect of C3 on invasion was not restricted to the murine BW5147 lymphoma cell line, as it occurred also with CCRF-CEM, a human T-cell lymphoma line. Our results demonstrate that invasion-bound motility of lymphocytes depends on a Rho-mediated signal transduction pathway.
authors.affiliation: Pasteur Instituut, Brussels/Belgium.
authors.forename: H
authors.initials: H
authors.lastname: Verschueren
authors.forename: P
authors.initials: P
authors.lastname: De Baetselier
authors.forename: J
authors.initials: J
authors.lastname: De Braekeleer
authors.forename: J
authors.initials: J
authors.lastname: Dewit
authors.forename: K
authors.initials: K
authors.lastname: Aktories
authors.forename: I
authors.initials: I
authors.lastname: Just
mesh_terms: D036002:ADP Ribose Transferases / Q000378:metabolism* / Q000494:pharmacology; D000246:Adenosine Diphosphate Ribose / Q000378:metabolism*; D000818:Animals; D001905:Botulinum Toxins; D002465:Cell Movement / Q000187:drug effects; D048429:Cell Size / Q000187:drug effects; D003014:Clostridium botulinum / Q000201:enzymology; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006801:Humans; D016399:Lymphoma, T-Cell / Q000378:metabolism* / Q000473:pathology* / Q000503:physiopathology; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D009361:Neoplasm Invasiveness; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000166:cytology* / Q000378:metabolism* / Q000502:physiology; D014407:Tumor Cells, Cultured; D020743:rhoB GTP-Binding Protein
chemical_list: D008565:Membrane Proteins; D000246:Adenosine Diphosphate Ribose; D036002:ADP Ribose Transferases; C063007:exoenzyme C3, Clostridium botulinum; D001905:Botulinum Toxins; D019204:GTP-Binding Proteins; D020743:rhoB GTP-Binding Protein