Fig. 4

Sdf2l1 is upregulated in pancreatic tissues from humans and PRSS1^Tg mice with CP and interacts with St13. A Scheme depicting the Co-IP-MS experimental protocol used to identify proteins that directly bind St13 and related to ACP. B Venn diagram for the Co-IP-MS screening process to identify target protein (Sdf2l1) related to AA and fatty acid metabolism. Western blot (C) and qRT-PCR (D) analysis of St13 and Sdf2l1 expression in pancreatic acinar cells from humans and PRSS1^Tg mice;GaPDH was used as an internal loading control. IEM analysis of (E) Sdf2l1 localization and expression; black arrows (↑): representative gold nanoparticles. Co-IP of acinar cell-derived proteins was performed using anti-St13 (F) and anti-Sdf2l1 (G) antibodies. H Immunofluorescence staining to detect the co-localization of St13 and Sdf2l1 in human and PRSS1^Tg mouse normal and CP tissues. I Schematic representation of four Flag-tagged St13 protein constructs used: #1 (aa 1–371), #2 (aa 1–112), #3 (aa 113–214) and #4 (aa 215–371). J HEK293 cells were transfected with plasmids for the overexpression of each St13 construct, and pull-down experiments were performed with an anti-Flag antibody to co-immunoprecipitate Sdf2l1. Empty plasmid-transfected HEK293 cells were used as the normal control (NC) group. Co-IP, co-immunoprecipitation; MS, mass spectrometry; qRT-PCR, quantitative real-time polymerase chain reaction. Scale bars (immunofluorescence), 200 μm. The data are presented as the means ± SDs; ns no significant difference; *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001. The data are presented as the means ± SDs