Role of the MAPK/cJun NH2-Terminal Kinase signaling pathway in starvation-induced autophagy

ABSTRACTAutophagy is required for cellular homeostasis and can determine cell viability in response to stress. It is established that MTOR is a master regulator of starvation-induced macroautophagy/autophagy, but recent studies have also implicated an essential role for the MAPK8/cJun NH2-terminal kinase 1 signal transduction pathway. We found that MAPK8/JNK1 and MAPK9/JNK2 were not required for autophagy caused by starvation or MTOR inhibition in murine fibroblasts and epithelial cells. These data demonstrate that MAPK8/9 has no required role in starvation-induced autophagy. We conclude that the role of MAPK8/9 in autophagy may be context-dependent and more complex than previously considered.Abbreviations: AKT: thymoma viral proto-oncogene;ALB: albumin; ATG4: autophagy related 4; BCL2: B cell leukemia/lymphoma 2; BECN1: beclin 1, autophagy related; BNIP3: BCL2/adenovirus E1B interacting protein 3; CQ: chloroquine diphosphate; DMEM: Dulbecco’s modified Eagle’s medium; EDTA: ethylenediaminetetraacetic acid...