Mastoparan activation of G proteins and NDPK.

Jon Nakamoto jnakamot at
Wed Feb 23 00:07:09 EST 1994

Matthew --

This may not be exactly what you're thinking of re: effects of
mastoparan on small (monomeric) G-proteins, but here it is, FWIW:

(incidentally, what *I* would like to see is more conversation here
about G-proteins in general -- particularly ras, transducin, Gs.
Calling all G-protein researchers [there must be thousands out there

Koch G; Mohr C; Just I; Aktories K.
       Posttranslational isoprenylation of rho protein is a
prerequisite for its interaction with mastoparan and other amphiphilic
     Biochemical and Biophysical Research Communications, 1992 Jul 15,
 Abstract: The amphiphilic agents melittin, compound 48/80 and
mastoparan inhibit ADP-ribosylation of porcine brain rho protein by
Clostridium botulinum exoenzyme C3. However, ADP-ribosylation of
recombinant rhoA expressed in E.coli was not inhibited by these agents.
Accordingly, steady state GTP hydrolysis by recombinant rhoA was not
stimulated by mastoparan, whereas GTP hydrolysis by porcine brain rho
was stimulated 2.5-fold in the presence ofthis wasp venom. After
microinjection of recombinant rhoA into Xenopuslaevis oocytes the
inhibitory effect of mastoparan on C3 ADP-ribosylation was restored.
The data suggest that the amphiphilic agents tested are only active at
the posttranslationally processed form of rho and that they exert their
effects via the C-terminal end.

from the land of quakes,
Dept of Pediatrics/Endocrinology
UCLA Medical Center
jnakamot at

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