Involved in resistance to oxidative stress (e.g. hydrogen peroxide H(2)O(2)), high light and heavy metals (e.g. cadmium ions Cd(2+)) (PubMed:18390807, PubMed:24117441). Influences responses to reactive oxygen species (ROS) production. Together with SIA1, regulates iron distribution within the chloroplast and mediates the oxidative stress response (PubMed:24117441). Together with ABC1K7, influences chloroplast lipid synthesis/accumulation and modulates chloroplast membrane composition in response to stress (PubMed:25809944). ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Mostly expressed in leaves and flowers, and, to a lower extent, in stems, siliques and roots. By cadmium ions Cd(2+). Progressively repressed in senescent leaves. Levels follow a circadian rhythm, with lower levels during the night (PubMed:18390807). Down-regulated in response to iron deprivation (PubMed:24117441). Increased sensitivity toward oxidative stress (e.g. hydrogen peroxide H(2)O(2)), high light and cadmium ions Cd(2+). Higher superoxide dismutase activities in chloroplast and disturbed expression of genes involved in the antioxidant pathway (PubMed:18390807). Pale green plants. The pale green double mutant atsia1 atosa1 accumulates ferritin and superoxides, exhibits an increased nonphotochemical quenching (NPQ), and have a reduced tolerance to reactive oxygen species (ROS) (PubMed:24117441). Lower levels of the highly unsaturated lipid digalactosyldiacylglycerol (DGDG) and of different forms of monogalactosyldiacylglycerol (MGDG) and kaempferol. Higher levels of oxylipin-conjugated DGDG and sinapates. The abc1k7 abc1k8 double mutant accumulates strong levels of oxylipin-conjugated MGDG and DGDG (PubMed:25809944). Belongs to the protein kinase superfamily. ADCK protein kinase family.