8.A.110.1.5
Junctophilin-3, JPH3; JP3, of 748 aas and possibly 2 TMSs, one potential TMS near the N-terminus, and one certain TMS at the C-terminus.  Junctophilins contribute to the formation of junctional membrane complexes (JMCs) which link the plasma membrane with the endoplasmic or sarcoplasmic reticulum in excitable cells. It provides a structural foundation for functional cross-talk between the cell surface and intracellular calcium release channels. JPH3 is brain-specific and appears to have an active role in certain neurons involved in motor coordination and memory. JPH4 (Q96JJ6) is also brain-specific and appears to play an active role in certain neurons involved in motor coordination and memory. However, it facilitates inflammatory signalling at plasma membrane-endoplasmic reticulum junctions in sensory neurons(Hogea et al. 2021). JPH3 and JPH4 proteins maintain a Cav1-RyR2-KCa3.1 complex that allows two calcium sources to act in tandem to define the activation properties of KCa3.1 channels and the IsAHP (Sahu et al. 2019).