Figure 1. Divalent cations transporters.

(a) Ca²⁺ transport mechanisms in immune cells. Ca²⁺ homeostasis regulation involves the PMCA, SERCA ATPases as well as the MCU and Na⁺/Ca²⁺ exchangers (NCX). SOCE is induced by released of Ca²⁺ from the ER by the IP₃R. STIM senses the store depletion and triggers the opening of the Ca²⁺ CRAC channel, ORAI. SOCE is modulated by two K⁺ permeable channels, K_Ca 1.3 and K_v 3.1 regulated by intracellular Ca²⁺ and depolarization respectively. These two channels help sustain SOCE generation by inducing hyperpolarization of the cell. Additionally, the Na⁺ permeable channel TRPM4 is gated by intracellular Ca²⁺ and reduces the Ca²⁺ mobilization. (b) Mg²⁺ transport mechanisms in immune cells. Mg²⁺ transporters include TRPM7, which have an intracellular Ser/Thr kinase domain, MAGT1, and SLC41A1/2 expressed on the PM and Mrs2 on the inner membrane of the mitochondria. (c) Zn²⁺ transport mechanisms in immune cells. Zn²⁺ transporters of the ZnT and ZIP families are expressed in various cellular compartments. Zn²⁺ homeostasis is completed by MT. Abbreviations: ChR, Chemokine receptor; DAG, Diacylglycerol; FcR, Fc receptor; TPC, Two pore channel.