Abstract: Since Methoprene tolerant (Met) was identified as the juvenile hormone receptor, great progress has been made in understanding the molecular mechanisms of juvenile hormone (JH) in insect metamorphosis. In this article, we summarized the identification of Met and the regulation of chaperone protein Hsp83 and Nuclearporin Nup358 on Met cellular localization, focusing on the roles of JH-Met-Kr-h1-Br signal pathway in larval-pupal metamorphosis of holometabolous insects, and JH-Met-Kr-h1-E93 signal pathway in adult metamorphosis of hemimetabolous and holometabolous insects. Moreover, the roles of many molecular interactions in JH-20E crosstalk were discussed. These interactions include the binding between Met and 20-hydroxyecdysone nuclear receptor EcR/USP, the interaction of Tai/SRC/FISC with Met and EcR/USP to form JH and 20E functional receptors respectively, the activation of JH on 20E responsive gene E75A, and the association between JH and USP. The research progress of the mechanism that JH plays its physiological function through binding to the membrane receptor to activate PKC and PLC signalling was also overviewed.  

Key words: Juvenile hormone, receptor, metamorphosis, molecular mechanism, membrane receptor, signal pathway