Figure 1: TRPM7-mediated Mg²⁺ homeostasis is essential for Jurkat T-cell proliferation.

A) TRPM7 current densities and B) TRPM7 I/V relationship of Jurkat cells during whole-cell patch clamp experiment with Mg²⁺-free intracellular solution. WT (WT, black) and TRPM7 KO Jurkat clones (KO, red), n(WT)=9; n(KO)=10. C) Cell counts and D) viability of natively proliferating TRPM7 WT and KO Jurkat clones in RPMI medium with 10% FBS, with and without supplementation with 6 mM MgCl₂, n=3, measured in duplicates. E) Cellular Mg²⁺ content quantified by ICP-MS. WT and TRPM7 KO Jurkat clones, cultured in regular (WT-)media for 18 h ahead of sampling, n=4. And WT and TRPM7 KO Jurkat clones, cultured in regular (WT-)media supplemented with 6 mM MgCl₂ for 18 h ahead of sampling, n=4. F) TRPM7 current densities and G) TRPM7 I/V relationship of Jurkat cells during whole-cell patch clamp with Mg²⁺-free intracellular solution. WT Jurkat cells, treated with DMSO as solvent control (Ctrl, black) or treated with 30 μM NS8593 (NS, red), n(Ctrl)=6; n(NS)=10. H) Cell counts and I) viability of natively proliferating Jurkat cells in RPMI medium with 10% FBS, with and without supplementation with 6 mM MgCl₂, and treated with DMSO as solvent control (Ctrl, black) or treated with 30 μM NS8593 (NS, red), n=4. J) Cellular Mg²⁺ content as measured with ICP-MS. Jurkat WT cells, treated with DMSO as solvent control (Ctrl, black) or treated with 30 μM NS8593 in DMSO (NS, red), cultured in regular (WT-) media without and with supplementation with 6 mM MgCl₂ for 18 h ahead of sampling, n=4. Statistics: Two-way ANOVA (C, D, H, I) or one-way ANOVA (E, J). * P<0.05; ** P<0.005; *** P<0.0005 and **** P<0.0001. Data are mean ± SD.