NCX-DB: a unified resource for integrative analysis of the sodium calcium exchanger super-family.

Na ⁺ /Ca ²⁺ exchangers are low-affinity high-capacity transporters that mediate Ca ²⁺ extrusion by coupling Ca ²⁺ efflux to the influx of Na ⁺ ions. The Na ⁺ /Ca ²⁺ exchangers form a super-family comprised of three branches each differing in ion-substrate selectivity: Na ⁺ /Ca ²⁺ exchangers (NCX), Na ⁺ /Ca ²⁺ /K ⁺ exchangers, and Ca ²⁺ /cation exchangers. Their primary function is to maintain Ca ²⁺ homeostasis and play a particularly important role in excitable cells that experience transient Ca ²⁺ fluxes. Research into the role and activity of Na ⁺ /Ca ²⁺ exchangers has focused extensively on the cardio-vascular system, however, growing evidence suggests that Na ⁺ /Ca ²⁺ exchangers play a key role in neuronal processes such as memory formation, learning, oligodendrocyte differentiation, neuroprotection during brain ischemia and axon guidance. They have also been implicated in pathologies such as Alzheimer's disease, Parkinson's disease, Multiple Sclerosis and Epilepsy, however, a clear understanding of their mechanism during disease is lacking. To date, there has never been a central resource or database for Na ⁺ /Ca ²⁺ exchangers. With clear disease relevance and ever-increasing research on Na ⁺ /Ca ²⁺ exchangers from both model and non-model species, a database that unifies the data on Na ⁺ /Ca ²⁺ exchangers is needed for future research. NCX-DB is a publicly available database with a web interface that enables users to explore various Na ⁺ /Ca ²⁺ exchangers, perform cross-species sequence comparison, identify new exchangers, and stay-up to date with recent literature. NCX-DB is available on the web via an interactive user interface with an intuitive design, which is applicable for the identification and comparison of Na ⁺ /Ca ²⁺ exchanger proteins across diverse species.