Fig 2: Mitochondrial fission is further enhanced by Mst1 overexpression in combination with Yap knockdown. a, b Immunofluorescence assay was used to observe the alteration of mitochondrial length using the mitochondrial antibody Tom-20. Adenovirus Mst1 (ad-Mst1) and shRNA against Yap (sh-Yap) were transfected into MDAT-32 cells. c–g Proteins were isolated from MDAT-32 cells and then western blot was used to evaluate the levels of mitochondrial fission-related proteins. Adenovirus Mst1 (ad-Mst1) and shRNA against Yap (sh-Yap) were transfected into MDAT-32 cells. *p < 0.05 vs. control group, #p < 0.05 vs. ad-Mst1 group and/or sh-Yap group

Fig 3: Hepatic MST1 expression and lipogenic factors in patients with NAFLD. (a) mRNA levels of MST1 and lipogenic genes. (b–d) Protein levels of MST1 and lipogenic proteins (n = 3, *p < 0.05, #p < 0.01; normal vs NAFLD).

Fig 4: Mst1-/- BMDCs display reduced antigen uptake. (A,B) The antigen uptake ability of Mst1+/+ and Mst1-/- BMDCs was measured. Mst1+/+ and Mst1-/- BMDCs (2 × 105 cells) were incubated for 30 min at 4 or 37°C, after which the cells were further incubated for 1 h at 4 or 37°C in a medium containing 1 mg/mL of FITC-dextran. The quantitative uptake of FITC-dextran by DCs was analyzed by flow cytometry. (A) Numbers in the histograms represent the MFI and percentage of FITC-dextran+ cells. Data are representative of at least three independent experiments. (B) Bar graphs show the mean ± SD from three independent experiments. Filled histogram indicates unstained cells. (C,D) Expression level of intracellular CD206 was analyzed by flow cytometry. (C) Numbers in the histograms represent the MFI. Data are representative of at least three independent experiments. (D) Bar graphs show the fold induction in Mst1-/- BMDCs compared to Mst1+/+ BMDCs and represent the mean ± SD from three independent experiments. Filled histogram shows isotype control. *P < 0.05 and ***P < 0.001 (t-test).

Fig 5: Proposed mechanism of Hsp27 regulation of the Hippo tumor suppressor pathway.(Pathway On) The Hippo tumor suppressor pathway is activated by the core kinase MST1, which phosphorylates LATS1 and MOB1, leading to YAP/TAZ phosphorylation and their sequestration in the cytoplasm by 14.3.3 proteins. This prevents YAP/TAZ nuclear translocation and association with transcription factors such as SMADs, TCF and TEADs. (Pathway Off) Hsp27 forms a complex with MST1 and accelerates the proteasomal degradation of ubiquitinated MST1. This prevents phosphorylation of LATS1 and MOB1, and phosphorylation of YAP/TAZ, which allows their nuclear translocation and their transcriptional activation of genes associated with malignant phenotypes.