Protein Extraction and Western Blot Analysis

As previously described [22 (link)], protein extraction was conducted using RIPA buffer (Sigma‐Aldrich, USA). Equal amounts of protein samples were separated using 12% SDS‐polyacrylamide gel electrophoresis. When the protein separation was complete, polyvinylidene difluoride membranes (Invitrogen, USA) were used for the protein transfer. Next, the samples were blocked in 5% skim milk (2 h). When the block was completed, anti-UBE2T (1;1000, Cat#: ab154022, Abcam, UK), anti-ERK, anti-p-ERK, anti-RSK2, anti-p-RSK2 (1:800; Cell Signaling Technology, Danvers, MA, USA), anti-β-actin (1:1000; Abcam, Cambridge, MA), and anti‐GAPDH (1;1000, Cat#: ab8245, Abcam, UK) were used to treat the samples for overnight at 4°C. The next morning, the samples were treated with a secondary antibody (1 h). At the end, protein bands were observed with an Odyssey instrument (Li-cor, USA).