Fig 2: LIFR and SHP1 positively regulate ferroptosis while LCN2 negatively regulates ferroptosis.a-d LIFR-knockdown (a, b) or SHP1-knockdown (c, d) HT1080 cells were treated with 10 µM erastin for 0, 5, or 10 h. a, c: staining of 7-aminoactinomycin (7-AAD) and annexin V. b, d: the percentage of annexin V and 7-AAD double-negative population. e The percentage of annexin V and 7-AAD double-negative population in LIFR-knockdown HT1080 cells treated with 0.5 µM RSL3 for 12 h, 50 µM FIN56 for 6 h, or 10 µM FINO2 for 24 h. Supplementary Figure 6e shows representative flow cytometry plots. f The percentage of annexin V and 7-AAD double-negative population in SHP1-knockdown HT1080 cells treated with 0.5 µM RSL3 for 12 h, 50 µM FIN56 for 6 h, or 10 µM FINO2 for 24 h. Supplementary Figure 6f shows representative flow cytometry plots. g The percentage of annexin V and 7-AAD double-negative population in LCN2-knockdown HT1080 cells treated with 10 µM erastin for 0, 4, or 8 h, alone or in combination with liproxstatin-1 (lip-1, 10 µM) or DFO (100 µM). Supplementary Figure 7b shows representative flow cytometry plots. h The percentage of annexin V and 7-AAD double-negative population in LCN2-knockdown HT1080 cells treated with 0.5 µM RSL3 for 10 h, 50 µM FIN56 for 3 h, or 10 µM FINO2 for 12 h, alone or in combination with liproxstatin-1 (lip-1, 10 µM) or DFO (100 µM). Supplementary Fig. 7c shows representative flow cytometry plots. i, j Lipid peroxidation levels in LIFR-knockdown (i) and SHP1-knockdown (j) HT1080 cells treated with 10 µM erastin for 3 h or 0.5 µM RSL3 for 4 h. k Lipid peroxidation levels in LCN2-knockdown HT1080 cells treated with 10 µM erastin for 3 h or 0.5 µM RSL3 for 4 h, alone or in combination with liproxstatin-1 (10 µM) or DFO (100 µM). Lipid peroxidation levels were gauged by C11-BODIPY staining in i–k. Statistical significance in b and d–k was determined by a two-tailed unpaired t-test. Error bars are s.e.m. n = 3 samples per group. Source data are provided as a Source Data file.

Fig 3: SHP1-dependent ADP repression is SYK-dependent. NLCs were transfected with 50 nM scrambled siRNA control or three different SHP1-siRNAs (siRNA A–C). (A) Protein was harvested after 48 h and SHP1 and GAPDH expression visualized and quantitated by western blot to examine knockdown efficiency. (B) NLCs were co-cultured with autologous CLL cells for 48 h after SHP1 siRNA C or scrambled siRNA transfection. Cultures were then treated with or without obinutuzumab (10 µg/ml) for 2 h before ADP responses examined. Data presented as mean value ± SEM from five CLL patients. (C) Western blot data analysis of SYK (pSYKY525/526) and AKT phosphorylation (pAKTS473) in NLCs following SHP1 siRNA transfection. Representative blots and quantified data are shown. Data presented as mean value +/- SEM. Each point represents an individual patient. Statistical analysis used a Mann Whitney U Test. *p < 0.05, ***p, 0.001, and ****p < 0.0001.

Fig 4: SHP1 knockdown partially rescues the inhibition of TCR-MC formation and proximal signaling conferred by DLG1 deficiency (A). Microclusters of phosphorylated Y493 ZAP-70 (green) and phosphorylated TCR- ? (red) were visualized in immunostained wild-type or DLG1 KO Jurkat cells that were pretreated with control or SHP1-specific siRNA. Cells were dropped onto coverslips coated with anti-CD3 (stimulated) or anti-CD45 (unstimulated) and visualized after 5 min. Scale bars, 10 µm. Quantitative data for specific signals’ intensities (using Image J; collected from eight fields) are graphically represented (B). Immunoblot analysis of lysates from wild-type and DLG1 KO Jurkat cells. Cells were pretreated with control or SHP1-specific siRNA, then activated with soluble anti-CD3 (monoclonal antibody OKT3) and antibody to mouse immunoglobulin G (IgG), followed by probing for phosphorylated and total proteins. Data are representative of three experiments. Student’s unpaired t tests were used for (A). ** p < 0.01, *** p < 0.001, **** p < 0.0001.

Fig 5: Schematic diagram illustrating Siglec-E-induced negative signaling on CD36-mediated oxLDL uptake on macrophages. Siglec-E physically interacts with CD36 through their polypeptides in resting state. When oxLDL binds to CD36, oxLDL-CD36 complex elicits the recruitment of a putative surface protein containing sialoglycan to interact with Siglec-E and activate Siglec-E/SHP-1 axis, which in turn inhibits CD36 downstream signaling for oxLDL uptake