Abstract
Production of reactive oxygen species (ROS) by NADPH oxidases has been shown to play crucial roles in the regulation of biotic and abiotic stress responses, programmed cell death and root hair development. In contrast to the NADPH oxidase complex in mammalian phagocytes that consists of multiple regulatory subunits, only the homologs of the catalytic subunit NOX2, rboh (respiratory burst oxidase homolog), and the cytosolic small G proteins, Rac, have been found in plants. By applying a heterologous expression system using HEK293T cells, we recently showed that AtrbohC and AtrbohD possess ROS-producing enzyme activity synergistically activated by binding of Ca2+ and phosphorylation (Ogasawara et al., JBC, 2008). We here screened for proteins that interact with the N-terminal cytosolic region of AtrbohD and AtrbohF using yeast two-hybrid assay, and so far identified 19 candidates. We further heterologously coexpressed the putative interactors with Atrbohs in HEK293T cells and characterized their effects on the ROS-producing activity. Possible involvement of the putative interactors in the regulation of Atrbohs will be discussed.
