Junctophilin-3 is a protein that in humans is encoded by the JPH3 gene.

Junctional complexes between the plasma membrane and endoplasmic/sarcoplasmic reticulum are a common feature of all excitable cell types and mediate cross talk between cell surface and intracellular ion channels. The protein encoded by this gene is a component of junctional complexes and is composed of a C-terminal hydrophobic segment spanning the endoplasmic/sarcoplasmic reticulum membrane and a remaining cytoplasmic domain that shows specific affinity for the plasma membrane. CAG/CTG repeat expansions at the Huntington's disease (HD)-like 2 locus have been identified in this gene, which is a member of the junctophilin gene family. [provided by RefSeq, Jul 2008]. Publication Note: This RefSeq record includes a subset of the publications that are available for this gene. Please see the Gene record to access additional publications.

Function: Contributes to the stabilization of the junctional membrane complexes, which are common to excitable cells and mediate cross-talk between cell surface and intracellular ion channels. Probably acts by anchoring the plasma  membrane and endoplasmic reticulum. May play an active role in certain neurons involved in motor coordination (By similarity).