Probable metal transporter. Probably acts redundantly with the other metal transport proteins cnnm-1, cnnm-3, cnnm-4 and cnnm-5 to regulate Mg(2+) homeostasis. No visible phenotype. Double knockout with cnnm-3 results in 22% sterility. Quintuple knockout with cnnm-1, cnnm-3, cnnm-4 and cnnm-5 results in a reduced lifespan and 100% sterility. Belongs to the ACDP family.