Required for the positioning and movement of chloroplasts. Interacts with profilin and actin independent of its polymerization status. Regulates chloroplast localization by anchoring chloroplasts to the plasma membrane and forming a bridge to the actin cytoskeleton. A number of isoforms are produced. According to EST sequences. Expressed in cauline leaves, rosette leaves, stems and flowers, but not in roots. The N-terminal region (1-25) is necessary and sufficient for targeting and anchoring the protein in the chloroplast envelope membrane. The coiled coil domain(123-341) interacts with the plasma membrane and anchors chloroplasts firmly on the plasma membrane. The actin binding motif (346-356) can function in vitro as an actin binding site. The proline-rich domain (648-705) mediates the interaction with profilin. Defective in chloroplast photorelocation movement, leading to damage of the photosynthetic apparatus and subsequent bleaching of leaf color and necrosis under high light conditions. Chloroplasts gathered at the bottom of cells, regardless of the light conditions.