Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9899160 | International Journal of Medical Microbiology | 2005 | 12 Pages |
Abstract
The virulence-associated SpvB protein of Salmonella enterica is a mono (ADP-ribosyl)transferase defined to target mammalian actin. Exposure of Acanthamoeba rhysodes cell lysate with SpvB and [32P]nicotinamide adenine dinucleotide (NAD) was here observed to result in labeling of a protein of 43Â kDa that subsequently was identified as actin by immunoprecipitation. In parallel, ADP-ribosylation promoted degradation of the protozoan actin. SpvB-mediated actin degradation occurred in the presence of the serine protease inhibitor phenylmethylsulfonylfluoride (PMSF), but was inhibited upon addition of novobiocin, an inhibitor of mono (ADP-ribosyl)transferase activity, or upon addition of EDTA. Infection of A. rhysodes with SpvB-proficient S. enterica serovariant Dublin resulted in cytotoxicity and in characteristic SpvB-mediated actin degradation. Cells infected with SpvB-deficient bacteria showed a decrease in cytotoxicity and lack of actin degradation. Combining these results show that SpvB formally can ADP-ribosylate A. rhysodes actin but that the protozoan cell has the capacity to subsequently degrade ADP-ribosyl-tagged actin. These observations illustrate a hitherto undefined consequence of actin modification, and define a new pathway in the cellular actin dynamics.
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Authors
Dilek Tezcan-Merdol, Lars Engstrand, Mikael Rhen,