Host: The Japanese Pharmacological Society
Name : The 97th Annual Meeting of the Japanese Pharmacological Society
Number : 97
Location : [in Japanese]
Date : December 14, 2023 - December 16, 2023
Background: The non-selective cation channels TRPV1 (V1) and TRPA1 (A1) are respond to nociceptive stimulus and co-expressed in the dorsal root ganglia (DRG). Capsaicin, a V1 agonist, binds to the transmembrane region of V1, and allyl isothiocyanate (AITC), an A1 agonist, binds to the N-terminus of A1, and activates these channels. It has been suggested that V1 and A1 form a functional heterotetramer in native cells, but the details are unknown. We therefore created their artificial heterotetramers and analyzed whether V1 and A1 could form a functional heterotetoramer.
Methods: A1 and V1 were cloned from rat cDNA, and the A1::V1 tandem(A1::V1) was created by linking them with a linker. We also created a tandem of ∆N A1 and V1 (∆N A1::V1), in which the N-terminus of A1 was shortened. These channels were expressed in HEK293 cells, and the responses of these channels to agonists were examined using the whole-cell patch clamp technique.
Results/Discussion: A1::V1 responded to both capsaicin and AITC. To investigate the contribution of A1 N-terminus to the agonist responsiveness of the A1::V1, we analyzed the function of ∆N A1::V1. ∆N340 A1::V1 (lack of 1st to 8th N-terminal ankyrin domain of A1) was found to be not responsive to both agonists. On the other hand, the ∆N308 A1::V1 (lack of 1st to 7th ankyrin domain of A1) responded to both agonists, suggesting that, the 8th N-terminal ankyrin domain of A1 is required for agonist responsiveness of the A1::V1.
These results suggest that TRPV1 and TRPA1 constitute heterotetramer and function as ion channels in native cells.
