Journal: Scientific Reports
Article Title: Autism-associated mutation in Hevin/Sparcl1 induces endoplasmic reticulum stress through structural instability
doi: 10.1038/s41598-022-15784-5
Figure Lengend Snippet: ASD-associated W647R mutant of Hevin activates the UPR signaling. ( A ) Location of ASD-associated Hevin mutations. ( B ) Amino acid of the EF-hand motif in each species. The human Trp 647 is highly conserved. Cyan indicates the EF-hand motif, Magenta indicates non-conserved amino acid. ( C ) Immunoblotting of Hevin WT and mW633R mutant. Neuro-2a cells were transfected with expression vectors and collected at the indicated times. The upper panel indicates the experimental schedule. The transfection efficiencies were confirmed by observing co-expressed EGFP fluorescence. The cell lysates and conditioned medium were subjected to immunoblot analysis using anti-Hevin and Tubulin antibodies. The secretion rate of the Hevin WR mutant was delayed more than that of WT. CM; conditioned medium, TCL: total cell lysate ( D ) Immunostaining of Hevin WT and mW633R mutant. HeLa cells were transfected for 24 h with expression vectors for Hevin and mCherry-ER and subjected to immunocytochemistry. Scale bar: 10 μm. ( E ) Quantification of Pearson’s correlation coefficient as the degree of colocalization in the panel D. n = 15 cells, mean ± SEM, *** p < 0.001 by Student’s t- test. ( F ) Immunostaining of Hevin and mW633R mutant. HeLa cells were transfected for 24 h with expression vectors for Hevin and subjected to immunocytochemistry. Scale bar: 10 μm. ( G ) Quantification of Manders’ coefficient as the degree of colocalization of Hevin with GM130 in the panel F. n = 20 cells, mean ± SEM, *** p < 0.001 by Student’s t- test. ( H , I ) Total RNAs isolated from the Hevin-overexpressed Neuro-2a cells were conducted with qPCR analysis for measurement of Bip and Chop mRNAs. 5S rRNA were used for normalization. n = 5; ** p < 0.01, *** p < 0.001 versus Hevin WT, one-way ANOVA Dunnett’s test calculated p -value using the ΔCt value. ( J ) Immunoblotting of BIP, Hevin, and Tubulin. Neuro-2a cells were transfected for 72 h with expression vectors for Hevin WT or mW633R mutants. The cell lysates were then subjected to immunoblot analysis using anti-BIP, Hevin, and Tubulin antibodies. ( K ) Schematic structure of GST-Hevin. ( L ) Pull down of GST-Hevin and endogenous BIP in HEK293T cells. GST-Hevin was precipitated with Glutathione Sepharose beads and immunoblotted with anti-GST, BIP, and Tubulin antibodies.
Article Snippet: For immunoblotting goat anti-Hevin (1:1000, R&D Systems, Cat# AF2836), mouse anti-Tubulin (1:1000, Sigma, DM1A), rabbit anti-BIP (1:1000, Cell Signaling, CB0B12), and mouse anti-GST (1:500, Santa Cruz, B14) antibodies were used as primary antibodies.
Techniques: Mutagenesis, Western Blot, Transfection, Expressing, Fluorescence, Immunostaining, Immunocytochemistry, Isolation