Related Experiment Video
Updated: May 8, 2026

Assaying Proteasomal Degradation in a Cell-free System in Plants
Published on: March 26, 2014
A bZIP protein, VIP1, interacts with Arabidopsis heterotrimeric G protein β subunit, AGB1
Daisuke Tsugama1, Shenkui Liu, Tetsuo Takano
1Asian Natural Environmental Science Center (ANESC), The University of Tokyo, 1-1-1 Midori-cho, Nishitokyo-shi, Tokyo, 188-0002, Japan.
Abstract:
Heterotrimeric G proteins (Gα, Gβ, Gγ) are signaling molecules conserved among eukaryotic species. The G proteins transmit signals via protein-protein interactions. By a yeast two-hybrid screen, we identified a bZIP protein, VIP1, as an Arabidopsis thaliana Gβ (AGB1)-interacting partner. The interaction between AGB1 and VIP1 was confirmed by an in vitro GST pull-down assay and a bimolecular fluorescence complementation (BiFC) assay. VIP1 was previously reported to be a regulator of osmosensory signaling. Interestingly, the BiFC pattern between AGB1 and VIP1 was speckled when cells were incubated in a hypotonic solution, but not when cells were incubated in a mannitol-containing hypertonic solution, suggesting that the subcellular localization of the AGB1-VIP1 complex is regulated by extracellular osmolarity and/or turgor pressure.
Related Concept Videos
Rab Proteins
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
Coat Assembly and GTPases
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
Rab Cascades
Cell Signaling in Plants
Activation and Inactivation of G Proteins
GTPases and their Regulation
Large G-proteins, also known...

