A novel FRET-based reporter for real time interrogation of p38-mediated stress response in human cells

Stress signaling in human cells is accomplished through three major mitogen activated protein kinase (MAPK) pathways: c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p38. The p38 stress signaling pathway is the least well-understood of the three, and its activity and misregulation are associated with a variety of human diseases, including Alzheimer’s Disease and HIV-Associated Neurocognitive Disorder (HAND). p38 is activated as a result of phosphorylation by upstream kinases in response to a variety of applied stresses. Activated p38 results in differential activation and expression of transcription factors appropriate to the specific applied stress that regulate differentiation, apoptosis, inflammatory response, etc. How appropriate differential responses result from the single input of phosphorylation state of p38 remains unclear. Here, we demonstrate a novel FRET-based p38 reporter that allows us to simultaneously visualize p38 activation state and intracellular localization. We demonstrate that a variety of stresses lead to unique patterns of activation and localization, and our goal is to elucidate how information about the incident stress is encoded in these variables and their dynamics.