Identification of ASPDH as a novel NAADP-binding protein

Abstract

NAADP is a signaling molecule that can induce calcium release from intracellular acidic stores. However, proteins that bind to NAADP are understudied. Here, we identify ASPDH as an NAADP-binding protein through biochemical purification from pig livers. ITC experiment using the recombinantly expressed protein shows a 1:1 binding stoichiometry and a Kd of 455 nM between NAADP and mouse ASPDH. In contrast, recombinantly expressed JPT2 and LSM12, two proteins previously identified as NAADP-receptors, show no binding in ITC experiments.