title: Phospholipase Cγ1 connects the cell membrane pathway to the nuclear receptor pathway in insect steroid hormone signaling.
abstract: In addition to the classical nuclear receptor pathway, there is a nongenomic pathway in the cell membrane that regulates gene expression in animal steroid hormone signaling; however, this mechanism is unclear. Here, we report that the insect steroid hormone 20-hydroxyecdysone (20E) regulates calcium influx via phospholipase Cγ1 (PLCG1) to modulate the protein kinase C phosphorylation of the transcription factor ultraspiracle (USP1) in the lepidopteran insect Helicoverpa armigera. The PLCG1 mRNA levels are increased during the molting and metamorphic stages. The depletion of PLCG1 by RNA interference can block 20E-enhanced pupation, cause larvae death and pupation defects, and repress 20E-induced gene expression. 20E may induce the tyrosine phosphorylation of PLCG1 at the cytosolic tyrosine kinase (Src) homology 2 domains and then determine the migration of PLCG1 toward the plasma membrane. The G-protein-coupled receptor (GPCR) inhibitor suramin, Src family kinase inhibitor PP2, and the depletions of ecdysone-responsible GPCR (ErGPCR) and Gαq restrain the 20E-induced tyrosine phosphorylation of PLCG1. PLCG1 participates in the 20E-induced Ca(2+) influx. The inhibition of GPCR, PLC, inositol 1,4,5-trisphosphate receptor, and calcium channels represses the 20E-induced Ca(2+) influx. Through calcium signaling, PLCG1 mediates the transcriptional activation driven by the ecdysone-response element. Through PLCG1 and calcium signaling, 20E regulates PKC phosphorylation of USP1 at Ser-21 to determine its ecdysone-response element binding activity. These results suggest that 20E activates PLCG1 via the ErGPCR and Src family kinases to regulate Ca(2+) influx and PKC phosphorylation of USP1 to subsequently modulate gene transcription for metamorphosis.
authors.affiliation: From the Key Laboratory of Plant Cell Engineering and Germplasm Innovation of Ministry of Education/Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, Shandong 250100, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Liu
authors.forename: Mei-Juan
authors.initials: MJ
authors.lastname: Cai
authors.forename: Chuan-Chuan
authors.initials: CC
authors.lastname: Zheng
authors.forename: Jin-Xing
authors.initials: JX
authors.lastname: Wang
authors.forename: Xiao-Fan
authors.initials: XF
authors.lastname: Zhao
mesh_terms: D000818:Animals; D000969:Antinematodal Agents / Q000494:pharmacology; D001483:Base Sequence; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism; D004441:Ecdysterone / Q000235:genetics / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009036:Moths / Q000235:genetics / Q000378:metabolism*; D051966:Phospholipase C gamma / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011987:Receptors, Steroid / Q000235:genetics / Q000378:metabolism*; D013498:Suramin / Q000494:pharmacology
chemical_list: D000969:Antinematodal Agents; D019476:Insect Proteins; D012333:RNA, Messenger; D011987:Receptors, Steroid; C055469:ecdysone receptor; D004441:Ecdysterone; D013498:Suramin; D051966:Phospholipase C gamma
keywords: 20-Hydroxyecdysone; Calcium Influx; Calcium Signaling; Gene Transcription; Phospholipase Cγ1; Phosphotyrosine; Protein Phosphorylation; Steroid Hormone Receptor