Functional Network Analysis Reveals the Relevance of SKIIP in the Regulation of Alternative Splicing by p38 SAPK

Abstract

Summary: Alternative splicing is a prevalent mechanism of gene regulation that is modulated in response to a wide range of extracellular stimuli. Stress-activated protein kinases (SAPKs) play a key role in controlling several steps of mRNA biogenesis. Here, we show that osmostress has an impact on the regulation of alternative splicing (AS), which is partly mediated through the action of p38 SAPK. Splicing network analysis revealed a functional connection between p38 and the spliceosome component SKIIP, whose depletion abolished a significant fraction of p38-mediated AS changes. Importantly, p38 interacted with and directly phosphorylated SKIIP, thereby altering its activity. SKIIP phosphorylation regulated AS of GADD45α, the upstream activator of the p38 pathway, uncovering a negative feedback loop involving AS regulation. Our data reveal mechanisms and targets of SAPK function in stress adaptation through the regulation of AS. : Carbonell et al. reports that p38 SAPK regulates alternative splicing to generate protein diversity in response to osmostress. The authors also show that SKIIP mediates splicing by p38. This mechanism, in turn, allows control of p38 activity through alternative splicing of the upstream regulator of the p38 pathway GADD45α. Keywords: cell signaling, p38 SAPK, alternative splicing, stress responses, GADD45