Based on the light-reactive behavior of siliceous sponges, their intriguing quartz glass-based spicular system and the existence of a light-generating luciferase [Mu ¨ller WEG et al.(2009) Cell Mol Life Sci66, 537–552], a pro-tein potentially involved in light reception has been identified, cloned and recombinantly expressed from the demosponge Suberites domuncula.