Figure 9

Model of how the nuclear transport factor 2 and Ran may function in the import of the EcR-B1 in the 20E signal transduction pathway. 1, the EcR-B1 transport through the NPC by binding with the importinα1 and importinβ and goes into the nucleoplasm; 2, in the nucleoplasm, 20E binds with EcR-B1 and formed trimeric complex with USP to regulate the transcriptions of genes. In the cytoplasm, NTF2 binds with RanGDP and transports RanGDP into the nucleoplasm, where RanGDP is converted into RanGTP by RCC1; RanGTP then is transported back into the cytoplasm by importinβ and hydrolyzed to RanGDP by RanGAP [44]; this process results in the energy gradient for the transport of EcR-B1 and the accumulation of EcR-B1 in the nucleus. NPC: nuclear pore complex; RCC1: Ran nucleotide exchange factor; RanGAP: Ran GTPase-activating protein. EcRE: ecdysone response elements.