Supplementary Figure 8: Monomeric SH2 fusion of HDPC restores ERK activation at later time points, and interaction between SOS1 and Grb2 is prolonged during antigen-receptor-induced Ras-ERK activation and human cancer– and Noonan syndrome–associated alterations of SOS1.
From: One-way membrane trafficking of SOS in receptor-triggered Ras activation
(a,b) Time dependence of pERK MFI ratio after BCR stimulation is plotted for indicated constructs: Single SH2 domain from human GrRB2 was fused to C-terminus of HDPC (HDPC-SH2). p-FLOW assay data in this figure were obtained from BCR stimulated cells with intermediate SOS expression level. Shown data are based on four independent cell cultures and pFLOW experiments. Error bars represent SEM. Source data are available online.
(c,d) Mouse CD4+ T cell blasts and hSOS1 stably transfected DT40 B cells were stimulated with antigen receptor crosslinking antibodies for the indicated time. SOS1 was immunoprecipitated from resulting lysates. Immunoprecipitated SOS1 and associated Grb2 were visualized by Western blotting. Phosphorylated ERK was used to indicate the status of Ras-ERK pathway. For panel (d), the percentage to max pERK2 at the indicated time is calculated after normalization to total ERK2 amount. Shown results are representative of two independent replicate experiments of each cell type.
(e) Human cancer- and Noonan-syndrome associated alterations of SOS1. Each bar represents a SOS alteration detected in patients. Green bars indicate missense point mutations. Alterations disrupting the C-terminus are indicated with red bars (fs: frame shift, spl: aberrant splicing, *: STOP codon,). Yellow boxes indicate PxxP motifs in C-terminal interacting with Grb2. Modified from cBioPortal for Cancer Genomics Database (Gao, J. et al, Sci. Signal., 6, p. l1, 2013).
