SnRK1 regulates chromatin-associated OXS3 family proteins localization through phosphorylation in Arabidopsis thaliana.

ABSTRACT

In plants, SNF1-related protein kinase 1 (SnRK1) senses nutrient and energy status and transduces this information into appropriate responses. Oxidative Stress 3 (OXS3) and family members share a highly conserved putative N-acetyltransferase catalytic domain (ACD). Here, we describe that the ACD contains two candidate SnRK1 recognition motifs and that SnRK1 can interact with most of the OXS3 family proteins. In vitro, SnRK1.1 can phosphorylate OXS3, OXS3b and O3L4, and in vivo promote the translocation of OXS3, OXS3b and O3L6 from the nucleus to the cytoplasm. Phosphorylation sites within the OXS3 ACD affect OXS3 cytoplasmic accumulation, as well as their interactions with SnRK1.1. This suggests that signal transduction from SnRK1 to OXS3 family proteins, and that SnRK1 can control their activities through phosphorylation-induced nuclear exclusion.