title: The hormone-dependent function of Hsp90 in the crosstalk between 20-hydroxyecdysone and juvenile hormone signaling pathways in insects is determined by differential phosphorylation and protein interactions.
abstract: BACKGROUND
  Heat shock protein 90 (Hsp90) interacts with steroid hormone receptors, signaling kinases, and various transcription factors. However, the mechanism by which Hsp90 interacts with different proteins in various pathways remains unclear.
  
  
  METHODS
  Western blot was used to study Hsp90 expression profile in Helicoverpa armigera (Lepidoptera). RNA interference was performed to investigate the function of Hsp90 in 20-hydroxyecdysone (20E) and juvenile hormone (JH) signal pathways. The binding of Hsp90 to the transcription factor ultraspiracle protein (USP1) and JH candidate receptor methoprene-tolerant (Met1) was analyzed by co-immunoprecipitation. Phospho-(Ser) PKC substrate antibody was used to detect Hsp90 phosphorylation.
  
  
  RESULTS
  Hsp90 participated in 20E- or JH-induced gene expression. 20E induced the interaction between Hsp90 and USP1, whereas JH III and methoprene induced the interaction between Hsp90 and Met1, respectively. 20E and JH counteracted each other for these protein interactions. Both JH III and methoprene induced protein kinase C (PKC) phosphorylation of Hsp90. This process could be inhibited by phospholipase C (PLC) and PKC inhibitors. 20E suppressed JH III- or methoprene-induced PKC phosphorylation of Hsp90.
  
  
  CONCLUSIONS
  20E maintained the non-PKC-phosphorylation status of Hsp90. Hsp90 interacted with USP1 to induce gene expression in the 20E pathway. JH regulated the PKC-phosphorylation status of Hsp90. Hsp90 also interacted with Met1 to induce gene expression in the JH pathway.
  
  
  CONCLUSIONS
  Our study describes a novel mechanism of Hsp90 action by altering phosphorylation and protein interaction in various hormonal signaling pathways.
authors.affiliation: The Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Science, Shandong University, Jinan 250100, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Liu
authors.forename: Feng-Xia
authors.initials: FX
authors.lastname: Zhang
authors.forename: Mei-Juan
authors.initials: MJ
authors.lastname: Cai
authors.forename: Wen-Li
authors.initials: WL
authors.lastname: Zhao
authors.forename: Xiang-Ru
authors.initials: XR
authors.lastname: Li
authors.forename: Jin-Xing
authors.initials: JX
authors.lastname: Wang
authors.forename: Xiao-Fan
authors.initials: XF
authors.lastname: Zhao
mesh_terms: D000818:Animals; D004441:Ecdysterone / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D007313:Insecta / Q000235:genetics / Q000378:metabolism*; D007605:Juvenile Hormones / Q000235:genetics / Q000378:metabolism*; D007915:Lepidoptera / Q000235:genetics / Q000378:metabolism; D008726:Methoprene / Q000378:metabolism; D010766:Phosphorylation; D054730:Protein Interaction Domains and Motifs / Q000235:genetics*; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D018841:HSP90 Heat-Shock Proteins; D019476:Insect Proteins; D007605:Juvenile Hormones; D014157:Transcription Factors; D004441:Ecdysterone; D008726:Methoprene; D011493:Protein Kinase C
keywords: 20-hydroxyecdysone (20E); Heat shock protein 90; Juvenile hormone (JH); Phosphorylation; Signal transduction