Uncharacterized Aarf Domain-Containing Protein Kinase At4g31390, Chloroplastic (AT4G31390) Arabidopsis Thaliana Recombinant Protein

Kinase that can phosphorylates the tocopherol cyclase VTE1, a key enzyme of tocopherol (vitamin E) metabolism and involved in the recycling of oxidated alpha-tocopherol quinone, possibly stabilizing it at plastoglobules. Regulates also plastoglobule protein composition (PubMed:24267661). Prevents photodamage of chloroplasts under continuous red light, thus working in opposition to ABC1K3 (PubMed:25882344). Together with ABC1K1, contributes to plastoglobule (PG) function in prenyl-lipid metabolism, stress response, and thylakoid remodeling (PubMed:23673981, PubMed:24267661). Involved in chlorophyll degradation and in the maintenance of the number of chlorophyll-binding photosynthetic thylakoid membranes (PubMed:22447966). Ensures photosynthetic electron transport by regulating the homeostasis of plastoquinone, beta-carotene and xanthophyll lutein, as well as membrane antioxidant tocopherol metabolism (PubMed:24267661). Seems to affect specifically stability or turnover of D1 protein, product of psbA, one of the four core subunits of the photosystem II (PSII) (PubMed:25882344). Required for photooxidative stress responses, including the induction of oxidative stress response genes (e.g. FSD1, CSD1, CAT1, and UTG71C1), to prevent photosystem II core and chlorophyll degradations (PubMed:22447966, PubMed:23673981, PubMed:24267661).