Essential ion channel and kinase. Crucial for magnesium homeostasis. Has an important role in epithelial magnesium transport and in the active magnesium absorption in the gut and kidney (By similarity). ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Forms heterodimers with TRPM7. Interacts (via kinase domain) with RACK1 (By similarity). In the C-terminal section; belongs to the protein kinase superfamily. Alpha-type protein kinase family. ALPK subfamily. In the N-terminal section; belongs to the transient receptor (TC 1.A.4) family. LTrpC subfamily. TRPM6 sub-subfamily.