Disruption of Intracellular Calcium Homeostasis Leads to ERLIN2-Linked Hereditary Spastic Paraplegia in Patient-Derived Stem Cell Models

Figure 3

The p.V71A variant in ERLIN2 resulted in the degradation of IP3R1 and the disturbance of calcium homeostasis by recruiting RNF213. (a) The IP3R1 protein was significantly downregulated in ERLIN2 p.V71A-mutant NSCs (, experiments, ). (b) The Fluo-4 AM fluorescent probe labeled intracellular calcium ions, and the calcium imaging was scanned by confocal microscopy. Thapsigargin (TG) was added at the time of 100 s. The intracellular basal calcium concentration and calcium release after TG stimulation were analyzed (, cells, experiments, ). (c) Anti-ERLIN2 immunoprecipitates (IP) from WT and p.Val71Ala NSCs (iPS-GJH). The mass spectrometry showed that compared with the WT, the p.Val71Ala interacted with RNF213. (d, e) In NSCs, the expression of RNF213 was not significantly different between the WT and p.Val71Ala. The p.Val71Ala ERLIN2 interaction with RNF213 was indeed significantly increased compared to the WT (, experiments, ). (f) In the p.Val71Ala group, the interaction between IP3R1 and RNF213 was significantly increased (, experiments, ), with iPS-GDL as the WT and iPS-GJH as the p.Val71Ala.

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