Direct interaction and functional coupling between voltage-gated Ca V1.3 Ca 2+ channel and GABA B receptor subunit 2

Abstract

Although Ca V1.2 and Ca V1.3 are two subtypes of L-type Ca 2+ channels expressed in the CNS, functions of Ca V1.3 have not been well elucidated compared to Ca V1.2. Here, we found that Ca V1.3-NT associates with GABA BR2-CT using yeast two-hybrid, GST pull-down and co-immunoprecipitation assays. We also demonstrated co-localization of Ca V1.3 and GABA BR2 in HEK293 cells and cultured hippocampal neurons. Whole-cell patch-clamp and Ca 2+-imaging experiments revealed that activation of GABA BR increases Ca V1.3 currents and intracellular Ca 2+ via Ca V1.3, but not Ca V1.2. These results show a physical and functional interaction between Ca V1.3 and GABA BR, suggesting the potential pivotal roles of Ca V1.3 in the CNS. Structured summary MINT- 7975667: Cav1.3 (uniprotkb: P27732) physically interacts (MI: 0915) with GABABR2 (uniprotkb: O88871) by two hybrid (MI: 0018) MINT- 7975740: Cav1.3 (uniprotkb: P27732) and GABABR2 (uniprotkb: O75899) colocalize (MI: 0403) by fluorescence microscopy (MI: 0416) MINT- 7966007, MINT- 7966016: Cav1.3 (uniprotkb: P27732) physically interacts (MI: 0915) with GABABR2 (uniprotkb: O88871) by anti bait coimmunoprecipitation (MI: 0006) MINT- 7975712, MINT- 7975691: Cav1.3 (uniprotkb: P27732) physically interacts (MI: 0915) with GABABR2 (uniprotkb: O88871) by pull down (MI: 0096) MINT- 7966026: GABABR2 (uniprotkb: O88871) and Cav1.3 (uniprotkb: P27732) colocalize (MI: 0403) by fluorescence microscopy (MI: 0416)