Lipocalin-2 and intestinal diseases

Figure 1 Crystal structure of lipocalin 2 with a closed calyx structure in the antiparallel direction generated via the AlphaFold protein structure database (AlphaFold Monomer v2. 0 pipeline)[12].

Figure 2 Regulation of lipocalin-2 biosynthesis (schematic diagram). The factors influencing lipocalin 2 expression alterations across various models were summarized. TNFα: Tumor necrosis factor-alpha; LPS: Lipopolysaccharide; TRAD: Protein TraD; TRAF: Tumor necrosis factor receptor-associated factors; IAP: Inhibitor of apoptosis proteins; RIPK1: Receptor-interacting protein kinase 1; CARD9: Caspase-recruitment domain 9; IKK: IκB kinase; NLPR3: NLR-family pyrin domain-containing protein 3; IKB: Inhibitor of kB; NFKB: Nuclear factor kappa light chain enhancer of activated B; JAK: Janus kinase; SOC3: Suppressor of cytokine signaling 3; STAT1/3: Signal transducer and activator of transcription 1/3; S1P: Sphingosine-1-phosphate; S1PR: Sphingosine-1-phosphate receptor; H3K27m³: Histone H3 lysine 27 trimethylation; KDM6A: Lysine-specific demethylase 6A; LCN2: Lipocalin-2.

Figure 3 Mechanisms by which lipocalin-2 interacts with cells (schematic diagram). The mechanisms by which lipocalin-2 complexes exert their effects on cells have been summarized. SLC22A17: Solute carrier family 22 member 17; ROS: Reactive oxygen species; ATG4B: Autophagy-related gene 4B; LC3B: Light-chain 3B; ER: Endoplasmic reticulum; elF2α: Alpha-subunit of eukaryotic translational initiation factor 2; ATF4: Activating transcription factor 4; CHOP: C/EBP homologous protein; Keap1: Kelch-like ECH-associated protein 1; NrF2: Nuclear factor erythroid 2-related factor 2; VEGF: Vascular endothelial-derived growth factor; CXCR4: C-X-C chemokine receptor type 4; LCN2: Lipocalin-2; ARE: Antioxidant response elements.