The heat's on: nuclear stress bodies signal intron retention

The cellular response to heat shock requires massive adaptation of gene expression driven by the transcription factor HSF 1, which assembles in nuclear stress bodies together with human satellite III RNA and numerous splicing factors. In this issue of The EMBO Journal , Ninomiya et al demonstrate that nuclear stress bodies serve as a platform for phosphorylation of the SR protein SRSF 9 by the CLK 1 kinase, which promotes retention of a large number of introns during the recovery phase from heat shock.