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Updated: May 7, 2026

Comparing the Affinity of GTPase-binding Proteins using Competition Assays
Published on: October 8, 2015
Regulation of Golgi structure through heterotrimeric G proteins
C Jamora1, P A Takizawa, R F Zaarour
1Department of Biology, University of California San Diego, La Jolla 92093-0347, USA.
Abstract:
We have previously shown that ilimaquinone (IQ), a marine sponge metabolite, causes complete vesiculation of the Golgi stacks. By reconstituting the IQ-mediated vesiculation of the Golgi apparatus in permeabilized cells, we now demonstrate that this process does not require ARF and coatomers, which are necessary for the formation of Golgi-derived COPI vesicles. We find that IQ-mediated Golgi vesiculation is inhibited by G alpha(s)-GDP and G alpha(i3)-GDP. Interestingly, adding betagamma subunits in the absence of IQ is sufficient to vesiculate Golgi stacks. Our findings reveal that IQ-mediated Golgi vesiculation occurs through activation of heterotrimeric G proteins and that it is the free betagamma, and not the activated alpha subunit, that triggers Golgi vesiculation.
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