Fig. 7

MAPK1–109aa inhibits phosphorylation of MAPK1 by competitively binding to MEK1. a Total protein from Flag-MAPK1–109aa plasmid-transfected HEK293T cells were separated via SDS-PAGE. Arrows show different bands between IgG and Flag. b List of the top ten differentially expressed proteins identified by mass spectrometry. c MEK1 was identified by LC/LC-MS in MAPK1–109aa protein complex. d Mutual interaction of MEK and Flag-MAPK1–109 aa were determined by IP. e Flag-tagged MAPK1–109aa was transfected into HEK293T cells and immunofluorescence was performed using anti-Flag and anti-MEK1 antibody. Scale bar, 20 μm. f In SGC7901 and MGC803 cell lines with stable knockout of circMAPK1, the expression level of MAPK1–109aa bound to MEK1 decreased. g The expression level of MAPK1–109aa bound to MEK1 increased in MKN45 and BGC823 cell lines transferred into circMAPK1 vector. h In SGC7901 and MGC803 cell lines with stable knockout of circMAPK1, the expression level of downstream cytokines p-ElK1, p-c-Fos, p-c-JUN, and p-RSK1 in the MAPK pathway increased significantly. i The expression level of downstream cytokines p-ElK1, p-c-Fos, p-c-JUN, and p-RSK1 in the MAPK pathway decreased in MKN45 and BGC823 cell lines transferred into circMAPK1 vector