Involved in both red and blue light signaling. Expressed in seedlings, roots, leaves, stems, flowers and siliques. Induced 3.1-fold by red light, 2.6-fold by far-red light, and 2.3-fold by blue light. Not induced by abscisic acid. Not phosphorylated in vitro by CPK3 or CPK11. Plants show a hypersensitive hypocotyl growth response to both red and blue light. Belongs to the Di19 family.