Extended Data Fig. 1: Identification of IFITM3 as γ-secretase binding protein.
From: The innate immunity protein IFITM3 modulates γ-secretase in Alzheimer’s disease
a, LC–MS/MS analysis of the 15-kDa band identified four peptides that match with human IFITM3. b, Western blotting analysis of PS1-NTF protein labelled with E2012-BPyne (500 nM). c, Structures of imidazole GSMs, acid GSM and GSIs. d, Western blotting analysis of E2012-BPyne-labelled proteins in the absence or presence of imidazole GSMs, acid GSM and GSIs. Labelled proteins were captured and analysed by western blotting for IFITM3. e, Structures of GY6 and 163-BP-l-biotin. f, IFITM3 co-immunoprecipitates with γ-secretase subunits. CHAPSO-solubilized cell membranes were immunoprecipitated with anti-IFITM3 antibody and probed with antibodies against PS2-CTF and PEN-2. Rabbit IgG was used as a negative control. g, IFITM3 does not co-immunoprecipitate with SPP. CHAPSO-solubilized cell membranes were immunoprecipitated with a monoclonal anti-IFITM3 antibody (9D11) and probed with antibodies against SPP and IFITM3. Mouse IgG was used as a negative control. h, Analysis of the total protein level in wild-type MEF or PS1/PS2 double knockout MEF cells. The same amount of membrane proteins was loaded and analysed by western blotting. i, Ifitm3 mRNA expression levels were measured by RT–PCR in wild-type MEFs or PS1/PS2 double knockout MEF cells (n = 6). All western blotting images and graphs are representative of three independent experiments (except in a and d, which represent two replicates). Data are mean ± s.d. ns, not significant. P values were determined by two-sided Student’s t-test.
