Identification of Dp140 and α1-syntrophin as novel molecular interactors of the neuronal Ca2.1 channel.

The primary function of dystrophin is to form a link between the cytoskeleton and the extracellular matrix. In addition to this crucial structural function, dystrophin also plays an essential role in clustering and organizing several signaling proteins, including ion channels. Proteomic analysis of the whole rodent brain has stressed the role of some components of the dystrophin-associated glycoprotein complex (DGC) as potential interacting proteins of the voltage-gated Ca channels of the Ca2 subfamily. The interaction of Ca2 with signaling and scaffolding proteins, such as the DGC components, may influence their function, stability, and location in neurons. This work aims to study the interaction between dystrophin and Ca2.1. Our immunoprecipitation data showed the presence of a complex formed by Ca2.1, Caαδ-1, Caβ, Dp140, and α1-syntrophin in the brain. Furthermore, proximity ligation assays (PLA) showed that Ca2.1 and Caαδ-1 interact with dystrophin in the hippocampus and cerebellum. Notably, Dp140 and α1-syntrophin increase Ca2.1 protein stability, half-life, permanence in the plasma membrane, and current density through recombinant Ca2.1 channels. Therefore, we have identified the Dp140 and α1-syntrophin as novel interaction partners of Ca2.1 channels in the mammalian brain. Consistent with previous findings, our work provides evidence of the role of DGC in anchoring and clustering Ca channels in a macromolecular complex.