Melanoma differentiation-associated gene 5 is involved in the induction of stress granules and autophagy by protonophore CCCP.
The eukaryotic cell has evolved a variety of stress responses against external stimuli, such as innate immunity, the formation of stress granules (SGs), and autophagy. We previously demonstrated that the innate immune adaptor IFN-β promoter stimulator 1 (IPS-1) plays an essential role in the formation of dsRNA-induced SGs, indicating a connection between SG formation and innate immunity. In this study, it was further demonstrated that melanoma differentiation-associated gene 5 (MDA5), an innate immune sensor, is involved in SG formation induced by carbonyl cyanide m-chlorophenylhydrazone (CCCP), a mitochondrial protonophore. MDA5 knockdown had no significant impact on the phosphorylation of eukaryotic translation initiation factor 2α (eIF2α) triggered by CCCP, and MDA5 itself was not recruited to SGs, suggesting that the regulation of MDA5 in the SG response occurs downstream of eIF2α. Furthermore, the depletion of MDA5 or G3BP1 led to reduced autophagy in CCCP-stimulated cells, implying that the regulatory effect of MDA5 with respect to autophagy depends on its role in SG formation. This study uncovered an unexpected role of the innate immune protein MDA5 in SG formation and autophagy triggered by the protonophore CCCP, further supporting a correlation between different stress responses.
Feng
F
Xu
Xiaobo
X
Li
Peifen
P
Zhang
Jun
J
Xia
Yi
Y
Wang
Chao
C
Yang
Huixin
H
Gao
Shili
S
Zhou
Ping
P
Zhang
D001343:Autophagy / Q000187:drug effects*; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology*; D003594:Cytoplasmic Granules / Q000187:drug effects* / Q000378:metabolism; D053487:DEAD-box RNA Helicases / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D000072640:Interferon-Induced Helicase, IFIH1; D013312:Stress, Physiological / Q000187:drug effects; D014407:Tumor Cells, Cultured
D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; C452815:IFIH1 protein, human; D053487:DEAD-box RNA Helicases; D000072640:Interferon-Induced Helicase, IFIH1