Avtor/Urednik		Bavec, Aljoša
Naslov		Novel features of amphiphibic peptide Mas7 in signalling via heterotrimeric G-proteins
Tip		članek
Vir		J Pept Sci
Vol. in št.		Letnik 10, št. 11
Leto izdaje		2004
Obseg		str. 691-9
Jezik		eng
Abstrakt		Amphiphilic peptide Mas7, a structural analogue of mastoparan is a known activator of heterotrimeric Gi-proteins and its downstream effectors. This study investigated the functional interaction of Mas7 with a plasma membrane protein from CHO cells, the endogenous mono-ADP-ribosyltransferase. The substrate of endogenous mono-ADP-ribosyltransferase was the ADP-ribosylated protein with a molecular mass of 36 kDa, which corresponded to the beta subunit of heterotrimeric G-proteins. The effect of Mas7 on endogenous mono-ADPribosyltransferase activity was in the micromolar range with a maximal activation of 205% over the basal. In pertussis treated plasma membranes, it was found that the effect of Mas7 on endogenous mono-ADP-ribosyltransferase was partially blocked, which suggests the involvement of G-proteins, such as Gi or G0. In addition, an immunoassay was developed for the visualization of interaction between the a subunit and the betagamma dimer of G-protein on a Ni-NTA support. The physical interaction was tested of Mas7 with the heterotrimeric G-protein alphai2 subunit, which was overexpressed together with beta 1 gamma2-His6 subunits in sf9 cells. An interaction between Gi2 heterotrimer and Mas7 was not observed, which was not in accordance with previously reported results of mastoparan obtained for Gi-proteins from bovine brain. In conclusion, the signal is mediated from Mas7 to endogenous mono-ADP-ribosyltransferase via pertussis sensitive G-proteins. Furthermore, it is hypothesized that Gi2 G-proteins are not involved in the process.
Deskriptorji		GTP-BINDING PROTEINS MEMBRANE PROTEINS ADENOSINE DIPHOSPHATE RIBOSE RECOMBINANT PROTEINS CELLS, CULTURED CHO CELLS ELECTROPHORESIS, POLYACRYLAMIDE GEL IMMUNOBLOTTING