Alternative Translation Initiation Generates a Functionally Distinct Isoform of the Stress-Activated Protein Kinase MK2

This is the authors' abstract. We don't add key points for this paper.

-activated protein kinase MK2. This isoform is constitutively translated from an alternative CUG translation initiation start site located in the 5' UTR of its mRNA. The RNA helicase eIF4A1 is needed to ensure translation of the long and the known short isoforms of MK2, of which the molecular properties were determined. Only the short isoform phosphorylated Hsp27 in vivo, supported migration and stress-induced immediate early gene (IEG) expression. Interaction profiling revealed short-isoform-specific binding partners that were associated with migration. In contrast, the long isoform contains at least one additional phosphorylatable serine in its unique N terminus. In sum, our data reveal a longer isoform of MK2 with distinct physiological properties.