#chup1

[whats-in-a-sentence]

A model of chloroplast movement in Arabidopsis is shown in Figure 16.24.

"Plant Physiology and Development" int'l 6e - Taiz, L., Zeiger, E., Møller, I.M., Murphy, A.

[whats-in-a-sentence]

The polymerization of G-actin in the absence of ABPs in a test tube is not only concentration-dependent, whereby it must reach a critical concentration in order to polymerize, but also time-dependent, requiring time for nucleation of monomers into a size stable enough to allow further elongation (Figure 1.25A). (...) F-actin slowly hydrolyzes ATP to ADP (green subunit to orange subunit transition in Figure 1.25). Profilins regulate the balance between G- and F-actin (Figure 1.25B). New F-actin is initiated in two ways: by filament growth activated by proteins called formins (Figure 1.25C), and by branching from filaments at junctions formed by the actin filament nucleator Arp 2/3 (Figure 1.25D). (...) But microfilaments can be stabilized into bundles through association with the proteins villin and fimbrin (see Figure 1.25B and C). (...) The assembly of microtubules from free tubulin in a test tube follows a similar time-dependent pattern as that of actin, involving nucleation, elongation, and steady state phases (see Figure 1.25A). (...) CHUP1 recruits G-actin and actin-polymerizing proteins to extend an existing F-actin filament (see Figure 1.25).

"Plant Physiology and Development" int'l 6e - Taiz, L., Zeiger, E., Møller, I.M., Murphy, A.