Background: Mitochondria send signals to the nucleus to modulate gene expression when mitochondrial function is perturbed. Results: Cyclin-dependent kinase E1 (CDKE1) was identified as an essential component in regulation of responses to perturbation of mitochondrial electron transport. Conclusion: Mitochondrial regulation is integrated with growth, energy, and other cellular stress signaling pathways. Significance: The identification of a molecular link between mitochondrial retrograde regulation and growth and stress signaling pathways. © 2013 by The American Society for Biochemistry and Molecular Biology, Inc.