UV-B radiation is an integral component of natural sunlight reaching the Earth’s surface. Although being a potentially harmful and damaging agent, UV-B is a key environmental signal for plants initiating diverse responses that affect their metabolism, development and viability. The majority of these responses involve the differential regulation of gene expression and all require accurate perception of the effective light quality by a photoreceptor. The recent identification of UV RESISTANCE LOCUS8 (UVR8) as a UV B photoreceptor has been an important milestone in plant UV B research (Rizzini et al., 2011; Christie et al., 2012; Wu et al., 2012). The aim of this study was to investigate how the structure of the UVR8 protein determines its function in the UV-B response in Arabidopsis
