Fig. 7: Low frequency SorCS2 missense variants hamper SorCS2 functions.

A 3D structure of SorCS2 Vps10p domain (PDB 6FG9) with side chain of mutated amino acids in ADHD patients depicted. The structure depicts mouse SorCS2 and thus the R666 position is here shown as the mouse endogenous histidine. B coimmunostaining of SorCS2 variants and calnexin in transfected HEK293T cells. Hoechst staining is shown in blue. C quantification of B shown as Pearson’s correlation coefficient (left) and Manders’ overlap coefficient (right). Results are shown as mean ± SEM, n = 47 (SorCS2 WT), n = 46 (R702W), n = 42 (S484I), n = 46 (R631C), n = 48 (R666C), statistical analysis by unpaired two tailed Student’s t test, IF, immunofluorescence. Depicted scale bar is 5 µm. D western blot of pull downs of SorCS2 variants from transfected cells with BDNFpro-GST. E quantification of D shown as mean ± SEM (n = 4). Data analyzed by unpaired two tailed Student’s t test F western blot of pull down of R702W SorCS2 from transfected cells with BDNFpro-GST. G quantification of F shown as mean ± SEM (n = 4). Data analyzed by paired two tailed Student’s t test. H western blot showing cross-linking of dimers of SorCS2 ECD variants secreted by transfected CHO cells. I quantification of H. Shown as mean ± SEM (n = 5). Data analyzed by paired two tailed Student’s t test. J neuronal branching of hippocampal Sorcs2 knockout neurons assessed after transfection with SorCS2 variants in the presence or absence of 1 nM BDNF. Values are shown as mean ± SEM (n = 2–4). Statistical analysis by unpaired two-tailed Student’s t test.