Interaction of Junctophilins and the C-Terminus of Cav1.1 Subunits Regulates Localization and Function of L-Type Calcium Channels in Skeletal Muscle

Junctophilins (JPs) are known to contribute to the stabilization of the junctional membrane (JM) complex by bridging the plasma membrane and sarcoplasmic reticulum; however, the role of JPs on the JM-targeting and function of L-type calcium channels is still unclear. Thus, we explored structural and functional consequences of JP knockdown (KD) in C2C12 and GLT myotubes. JP1 or JP2 KD significantly inhibited the JM-targeting of L-type calcium channels whereas JP2 but not JP1 KD significantly decreased the current density of L-type calcium channels.