Fig. 6

HTRA1 promoted the formation of ERES by recruiting SEC16A, which was indispensable for the ER-to-Golgi apparatus transport. A Display of interacting proteins with HTRA1 mined from the BioGrid database (https://thebiogrid.org/). B Representative Co-immunoprecipitation (Co-IP) showing the interaction between HTRA1 and SEC16A in cardiac fibroblasts. C Display of interacting proteins with HTRA1 mined from the GeneMANIA database (https://genemania.org/). D Representative Co-immunoprecipitation (Co-IP) showing the interaction between HTRA1 and Col1 in cardiac fibroblasts. Representative immunofluorescence images showing the colocalization of HTRA1 and Col1 (E) or SEC16A (F) in cardiac fibroblasts treated with or without HTRA1 siRNA. Distribution of Col1 (E) or SEC16A (F) was also exhibited. Orange box represented a typical colocalization field of view. The scale bar indicates 4 μm. (G). Immunofluorescence assays and quantitative data showing the changes of SEC31 (ERES marker) intensity in HTRA1 siRNA group (left). Grayscale mode can better display the intensity and distribution differences of SEC31. Orange box represented a typical colocalization field of view. The lower scale bar indicates 10 μm, and the higher scale bar indicates 4 μm. H ELISA assays showing the Col1 concentration difference of cell supernatant in cardiac fibroblasts transfected with or without SEC16A siRNA. Immunofluorescence assay (left images) exhibiting the colocalization of Col1 and GRP94 (I) or GM130 (J) in cardiac fibroblasts treated with or without SEC16A siRNA. The scale bar indicates 4 μm. Orange box represented a typical colocalization field of view. Middle images showing the intensity of Col1 and GRP94/GM130 along with the whit lines. Right box plots quantifying colocalization strength using Pearson’s R. K Co-IP analysis showing the interaction between col1 and SEC16A in cardiac fibroblasts treated with HTRA1 plasmid. Primary cardiac fibroblasts were treated with TGFβ1 for 48 h