Extended Data Figure 7. TRIM21 as a downregulated E3 ligase in lung cancer.

a, Ranking of expression change of E3 ubiquitin ligases (n = 213 ligases) in lung cancer patients. LUAD, lung adenocarcinoma; LUSC, lung squamous cell carcinoma; LUNG, total lung cancer. Data were generated by normalizing individual expression of E3 ligases in tumor samples to their matched normal expression, as reported by the TCGA. Data is plotted in descending order on a log₂ scale. TRIM21, red arrows. Right, a summary table of the ranked ligases is shown. Integrated from 20 datasets included in the Lung Cancer Explorer (LCE) ²⁹. Genes targeted by shRNA are indicated and TRIM21 is highlighted. b, Screening of 18 most consistently downregulated E3 ligases according to LCE for their effects on PFKP expression. Abundance of PFKP relative to GAPDH is summarized as a bar chart. The experiment was performed once. TRIM21, red, is the only of the tested ligases, whose depletion leads to an increase in PFKP expression. c, Abundance of TRIM21 in untransformed HBECs and NSCLCs. Representative data from two independent experiments are shown. d, Abundance of polyubiquinated PFKP in HEK cells without (control) and with overexpression of GFP-tagged TRIM21 (TRIM21-GFP). Representative data from two independent experiments. e, Abundance of PFKP in transformed H2009 cells upon CRISPR-based knockout (KO) of TRIM21. Representative data from two independent experiments. f, Abundance of PFKP after treating HBEC76 with AKT inhibitor X (AKTi, 10 μM) for 15 hrs. Representative data from two independent experiments. g, Abundance of mutant PFKP-GFP (S386A), which cannot be phosphorylated by AKT, compared to control on stiff and soft substrates. The experiment was performed once. In e, f, protein abundance was normalized to the abundance of β-actin, and in b, c, d, g to the abundance of GAPDH.