CagAEPISA and CagA expressing cells have a stellate morphology (Fig. 7A, B), a pattern that likely results from microtubule polymerization stimulated by the Rho activator, RhoGEF2 [23].
We thus next addressed whether Abp1 may directly influence the kinetics of actin filament nucleation and polymerization stimulated by N-WASP and the Arp2/3 complex by reconstituting these processes with purified components (actin, Arp2/3 complex, N-WASP, Abp1).
Theoretical models have suggested that lateral propagation can be generally explained by a combination of myosin motors and polymerization-stimulating membrane proteins aggregating in regions of convex membrane curvature [64].
Activated Rac can induce new actin polymerization by stimulating the Arp2/3 complex through the Rac target IRSp53 [23].
Since it is well known that GTP can activate actin polymerization by stimulating the Rho/Rac/cdc42 family of G-proteins [29], our finding that not only GTP but also GDP can activate actin polymerization in the subplasmalemmal region of starfish oocytes may be somehow counterintuitive.
Actin polymerization was stimulated by adding filamentous buffer (500 mM KCl, 20 mM MgCl2, 10 mM ATP), at a volume 1/10th of the final reaction volume, to the G-buffer that contained the proteins.
While in animal cells F-actin polymerization is stimulated by binding of capping protein to PIP2, plant actin capping protein is inhibited by PA.
While the light scattering may not be ideal for determining a precise, defined critical concentration, the point we wish to highlight is that the experiments in 1B and 2A return values that are consistent with one another, providing support that CTP alone is the main factor stimulating polymerization.
In the converse experiment of Figure 2E, DON-inhibited CtpS incubated in substrates does not polymerize, but addition of 1 mM CTP stimulates polymerization.
The monolignols catalyzed by CCR and cinnamyl alcohol dehydrogenase are transferred to the cell wall and polymerized by peroxidase H2O2 induced as one of the defense responses may stimulate polymerization of monolignols in the infected regions.
The progress made in the catalytic polymerization of cycloolefins stimulated a variety of applications for both commercial and technological purposes.
