Fig. 1

UBAP2L was more associated with ALS-linked FUS R521C than with FUS WT. A Western blot analysis demonstrating UBAP2L expression in HEK293T cell lysates expressing FLAG-empty vector, FLAG-FUS WT, and FLAG-FUS R521C. B A bar graph depicting the relative UBAP2L expression ratios of the WT and R521C mutants, normalized to actin expression. Data from independently replicated experiments are presented as the mean SEM (n = 4). ns: not significant, one-way ANOVA, Tukey's multiple-comparison test. C Co-Immunoprecipitation (Co-IP) analysis of UBAP2L-FUS interaction in HEK293T cells co-expressing HA-UBAP2L and FLAG-FUS WT or FLAG-FUS R521C. Following Co-IP, anti-HA (for UBAP2L) or anti-FLAG (for FUS WT or FUS R521C) antibodies were used for Western blotting. D A bar graph depicting the relative interaction ratio of UBAP2L with FUS WT versus FUS R521C mutant. Data from independently replicated experiments are presented as mean SEM (n = 3). **P < 0.01, Students t-test. E Confocal microscopy images showing the cellular localization of FLAG-FUS and HA-UBAP2L in HEK293T cells expressing FLAG-FUS WT or FLAG-FUS R521C with sodium arsenite (SA, 0.5 mM, 1 h) or without (DW) oxidative stress. The arrows indicate the co-localization of FUS with UBAP2L in the peri-nuclear cytoplasm of SA-treated HEK293T cells. Scale bar: 10 μm. F Co-localization of FLAG-FUS and UBAP2L with stress granule marker eIF4G in SA-treated HEK293T cells. The arrows indicate the co-localization of FUS with UBAP2L at elF4G positive cytoplasmic aggregates. Scale bar: 10 μm. SA: sodium arsenite. G Representative transmission electron micrographs of stress granules (SGs) imaged from HEK293T cells expressing Flag-FUS-R521C with (SA) or without (DW) oxidative stress. Scale bars: 1 um (a-d) and 500 nm (e and f, high magnification images of the marked area in SA-treated cells). Nu: nucleus, M: mitochondria, SG: stress granule. H Representative transmission electron micrographs of mitochondria (M) imaged from HEK293T cells expressing Flag-FUS-R521C with (SA) or without (DW) oxidative stress. Scale bars: 1 um (a and b, d-f) and 2 um (c). Nu: nucleus, M: mitochondria, SG: stress granule, ER: endoplasmic reticulum, asterisks: mitochondria showing structural abnormalities in DW or SA treated cells