Role of actin in the chloroplast photorelocation movement of Arabidopsis

Abstract

Chloroplasts show intracellular photomovements, regulated by phototropin1 and 2. Here in Arabidopsis, we show evidence that during photomovement, chloroplasts migrate using a unique mechanism involving short actin filaments localized to parts of their surfaces. In the absence of such light signals, chloroplasts are anchored by non-localized surface filaments. Mutants analyses reveal that CHUP1 functions in chloroplast-specific actin organization and that phototropins localize filament assembly to the region facing movement direction on the chloroplast surface.