JPT2 (Jupiter microtubule-associated homolog 2) is a NAADP-binding protein that functions as a critical regulator of calcium signaling and intracellular trafficking. Molecularly, JPT2 binds NAADP with high affinity and acts as an auxiliary protein that confers NAADP sensitivity to two-pore channels (TPCs) on endolysosomal organelles, enabling calcium release from these compartments 1. JPT2 directly associates with ryanodine receptors and facilitates NAADP-evoked calcium microdomain formation during early T cell activation 2. Beyond calcium signaling, JPT2 functions as a transcriptional co-factor regulating the LEPR/STAT3 axis and participates in endolysosomal trafficking of viral particles, including SARS-CoV-2 1. Clinically, JPT2 dysregulation associates with recurrent spontaneous abortion (RSA). In pregnancy loss, decreased JPT2 expression impairs trophoblast adhesion, migration, and invasion via JNK signaling, while simultaneously promoting M1 macrophage polarization through altered metabolic pathways 3. Similarly, JPT2 downregulation in subclinical hypothyroidism-associated miscarriage compromises trophoblast function 4. Gene therapy delivering JPT2 via adeno-associated virus alleviates embryonic resorption in mouse models 3. These findings establish JPT2 as both a central node in calcium-dependent immune signaling and a therapeutic target for pregnancy-related disorders.