As they evolved, organisms acquired non-visual sensors to discern light long before acquiring visual sensors to see. The non-visual sensors have acquired novel functions during the course of evolution, and a series of photoreceptor proteins known as ‘non-visual opsins’ play central roles among them.

Starting with the report that the non-visual opsin OPN4 regulates the internal clock, called circadian rhythm, even in mice that lack opsin, the visual sensor to ‘see’ things, and have lost their vision, various studies have been developed in fields other than vision. For example, OPN3 and OPN4 are expressed in various regions of the brain in addition to the retina, and OPN3 in particular has been shown to be expressed in various organs throughout the body. In addition, functionally, OPN5 is closely related to the biological mechanism of myopia progression, which is the subject of my own research, and it has been also reported that OPN5 works in the regulation of body temperature, indicating that it has important roles in vital activity other than sensing and seeing light.

In July 2022, cutting-edge global researchers met in-person in Seattle at the inaugural International Symposium for Biology of the Non-visual Opsins. Under the leadership of Professor Russell N. Van Gelder of the University of Washington Department of Ophthalmology, the group discussed non-visual opsins, which have great potential for both illumination of unknown areas of life and applications in clinical medicine and medical care. On July 26 and 27 (Fri/Sat), 2024, the second symposium will be held in Tokyo, where I will serve as Symposium Chair.

In terms of global attention, the biology of non-visual opsins is still in its infancy. However, as I mentioned earlier, its potential is exceedingly wide-ranging, and hosting this intellectual exchange of novel insights in Japan is of immense significance. We hope to shepherd creation of an environment enabling successful results through discussion and deepening of communication among global researchers, as well as collaboration among members of government, industry, and academia from Japan and abroad.

The Symposium will be held at the conference hall in Kanda Myoujin Shrine, allowing participants full enjoyment of Japanese culture. We are greatly looking forward to welcoming you to Tokyo.

The 2nd International Symposium
for Biology of the Non-Visual Opsins
Toshihide Kurihara, Chair