Intracellular Ca²⁺ levels are important in proper cellular functions and have prominent roles in various cell signaling pathways and are crucial for muscle contractions. Indeed, an important step leading to muscle contraction is the massive release of Ca²⁺ ions from the endoplasmic/sarcoplasmic reticulum (ER/SR) to the cytosol. A battery of results suggest that specific K⁺ channels are important to counteract the Ca²⁺ outflow in order to neutralize the negative potential created by the movement of Ca²⁺ ions. It is believed that TRIC channels are responsible for neutralizing this negative potential^1,2.

Trimeric intracellular cation-specific (TRIC) channels are critical for proper management of intracellular stores. TRIC-A and TRIC-B both belong to this family and are both permeable to monovalent ions with a preference for K^+ 3. Both channels are localized to the ER/SR membrane. Each TRIC subunit contains three transmembrane domains, a cytoplasmic C-terminus and a luminal N-terminus. Functional entities are formed by homotrimerizarion⁴. The activity of TRIC-A is regulated by voltage whereas that of TRIC-B can be regulated by different mechanisms³.

Knockout studies of these channels have shown that TRIC-A knockout mice are viable while those of TRIC-B die at the neonatal stage⁵.

TRIC-A is mostly expressed in excitable tissues like the brain and muscle while TRIC-B is ubiquitously expressed.