Increased memory with a flash of light

The burgeoning field of optogenetics has seen another breakthrough with the creation of a new plant-human hybrid protein molecule called OptoSTIM1.

In South Korea, a research team led by Won Do Heo, associate professor at the Korea Advanced Institute of Science and Technology (KAIST) and group leader at the IBS Center for Cognition and Sociality, together with Professor Yong-Mahn Han and Professor Daesoon Kim, have refined the process for precision control of cellular calcium (Ca2+) channels in living organisms with their new OptoSTIM1 molecule.

Calcium ions are a crucial part of diverse cellular functions such as contraction, excitation, growth, differentiation and death. Severe Ca2+ deficiency is linked to cardiac arrhythmia, cognitive impairment, and ataxia.

In optogenetics, a light-sensitive plant photoreceptor and an animal protein that affects cell membrane ion channels, bind together and are introduced to target cells. They work together and respond to a stimulus from a particular wavelength of light to open (or close) a particular ion channel.

Previous attempts at precision control of calcium channels using drugs and electrical stimulation were not accurate enough for meaningful results. What revolutionized the process of specified Ca2+ channel control was the invention of the field of optogenetics.

In their optogenetic application, the Korean team used a photoreceptor protein called cryptochrome 2 (Cry2) from a small, flowering plant Arabidopsis thaliana, and combined it with the STromal Interaction Molecule 1 (STIM1), a protein found in almost all animals, which opens cellular Ca2+ channels. This resulted in a hybrid molecule that they named OptoSTIM1.