Nicotinic acid adenine dinucleotide phosphate (NAADP) binding protein (PubMed:34362892). Confers NAADP sensitivity to the two pore channel complex (TPCs) by acting as TPC accessory protein necessary for NAADP-evoked Ca(2+) release (PubMed:34362892). Found in a complex with LSM12, TPCN1 and TPCN2 (PubMed:34362892). Interacts with TPCN2 (PubMed:34362892). Colocalizes with TPCN2. Belongs to the LSM12 family.