Announcements

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The winner of the Best Poster Award for 2nd German Pharm-Tox Summit goes to Dr. Astrid Rohrbeck with her work Functional Role of Arg-Gly-Asp (RGD)-Binding Site of C3.

Here is the abstract of the planned paper:

Title: Functional Role of Arg-Gly-Asp (RGD)-Binding Site of C3

Authors: Astrid Rohrbeck, Sandra Hagemann, and Ingo Just

Affiliation: Institute of Toxicology, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany

Abstract:

Clostridium botulinum C3 exoenzyme selectively inactivates low molecular weight GTPases RhoA, B, and C by N-glycosidic ADP-ribosylation, resulting in changes of cellular functions such as motility, endocytosis, proliferation and apoptosis. Although C3 is a mere enzyme devoid of binding and translocation domains, C3 is able to effectively enter cells and inactivate Rho GTPases. However, recent data indicates that C3 is specifically endocytosed by the involvement of the intermediate filament vimentin.

Amino acid sequence alignment of different C3 isoforms revealed that C3 exoenzymes contain a RGD-motif. The Arg-Gly-Asp (RGD) tripeptide is the major integrin binding site, present in a variety of integrin ligands. To check whether the RGD-motif of C3 is involved in binding to cells, we first performed a competition assay with C3 and RGD-peptide. Indeed, the GRGDNP peptide resulted in an approximate 50% displacement of C3 from the HT22 cells. Taken together, these findings indicate that the RGD-motif of C3 participates in the binding of C3 to intact cells.