**5.3 mRNA splicing**

The transcriptional response to external stimuli generates an outburst of mRNAs that have to be spliced. The associations between splicing events that modulate MAPK genes are becoming increasingly relevant in human disease [76]. One strategy to regulate splicing under stress is phosphorylation of the splicing factor TDP-43 by MEK1/2, which prevents TDP-43 aggregation [77]. Another mechanism of regulating splicing is by interfering with the localization of splicing factors such as RNM4, hn-RNPA1, or hSlut7 [78–80].
