Juvenile hormone-activated phospholipase C pathway enhances transcriptional activation by the methoprene-tolerant protein

Autor(es): Liu, Pengcheng; Peng, Hong-Juan; Zhu, Jinsong


Resumo: Juvenile hormone (JH) is a key regulator of a wide diversity of developmental and physiological events in insects. Although the intracellular JH receptor methoprene-tolerant protein (MET) functions in the nucleus as a transcriptional activator for specific JH-regulated genes, some JH responses are mediated by signaling pathways that are initiated by proteins associated with plasma membrane. It is unknown whether the JH-regulated gene expression depends on the membrane-mediated signal transduction. In Aedes aegypti mosquitoes, we found that JH activated the phospholipase C (PLC) pathway and quickly increased the levels of inositol 1,4,5-trisphosphate, diacylglycerol, and intracellular calcium, leading to activation and autophosphorylation of calcium/calmodulin- dependent protein kinase II (CaMKII). When abdomens from newly emerged mosquitoes were cultured in vitro, the JH-activated gene expression was repressed substantially if specific inhibitors of PLC or CaMKII were added to the medium together with JH. In newly emerged female mosquitoes, RNAi-mediated depletion of PLC or CaMKII considerably reduced the expression of JH-responsive genes, including the Keppel homolog 1 gene (AaKr-h1) and the early trypsin gene (AaET). JH-induced loading of MET to the promoters of AaKr-h1 and AaET was weakened drastically when either PLC or CaMKII was inactivated in the cultured tissues. Therefore, the results suggest that the membraneinitiated signaling pathway modifies the DNA-binding activity of MET via phosphorylation and thus facilitates the genomic responses to JH. In summary, this study reveals an interplay of genomic and nongenomic signaling mechanisms of JH.


Palavras-Chave: Insect Hormone; Development; Phospholipase C; Protein Kinase; Transcription


Imprenta: Proceedings of The National Academy of Sciences of The United States of America, v. 112, n. 15, p. E1871-E1879, 2015


Identificador do objeto digital: 10.1073/pnas.1423204112


Descritores: Aedes aegypti - DNA


Data de publicação: 2015