Trypanosoma brucei: Characterization of a Life Cycle Stage-Specific G-Protein

摘要: Abstract G-proteins have important and diverse roles in cellular signaling higher eukaryotes but as yet little is known about the involvement of these GTP-binding proteins protozoan parasites. Bacterial toxin-catalysed ADP-ribosylation, routinely used characterisation eukaryotes, was to determine whether functional G-protein homologues could be detected Trypanosama brucei . A 43-kDa polypeptide that ADP-ribosylated presence pertussis toxin identified membrane fractions. This also recognised by an antibody generated against a peptide sequence representing mammalian G O α subunit. GTP GTPγS (a nonhydrolysable analogue GTP) abolished ADP-ribosylation reaction, indicating binds GTP. Furthermore, this T. present bloodstream not procyclic life cycle stages. Using situ binding assay, further group small-molecular-size which are both stages been identified. demonstration suggests possible intracellular mechanisms may involved transduction host or other parasite signals.