Figure 2.

Channel communication in JP2-mediated JMC of smooth muscle cells. There are three main channels for external Ca²⁺ influx in smooth muscle cells: voltage-dependent Ca²⁺, receptor-operated Ca²⁺ entry, and storage-operated Ca²⁺ entry. Internal calcium release occurs mainly from the sarcoplasmic reticulum and endoplasmic reticulum to the cytoplasm through IP3Rs and RyRs. JP2 interacts with Cav 1 and is located in BK channels near RyRs to mediate the crosstalk between them, maintain normal potassium outflow, and cause membrane hyperpolarization, leading to smooth muscle relaxation.