Stress granules aid cell survival in response to environmental stressors by 
acting as sites of translational repression. We report an unanticipated link 
between stress granules and the serine/threonine kinase RSK2. In stressed breast 
cells, endogenous RSK2 colocalizes in granules with TIA-1 and poly(A)-binding 
protein 1, and the sequestration of RSK2 and TIA-1 exhibits codependency. The 
RSK2 N-terminal kinase domain controls the direct interaction with the 
prion-related domain of TIA-1. Silencing RSK2 decreases cell survival in 
response to stress. Mitogen releases RSK2 from the stress granules and permits 
its nuclear import via a nucleocytoplasmic shuttling sequence in the C-terminal 
domain. Nuclear accumulation is dependent on TIA-1. Surprisingly, nuclear 
localization of RSK2 is sufficient to enhance proliferation through induction of 
cyclin D1, in the absence of other active signaling pathways. Hence, RSK2 is a 
pivotal factor linking the stress response to survival and proliferation.