FIGURE 11.

Schematic representation of how PLCG1 regulates USP1 phosphorylation to mediate 20E-induced gene expression for metamorphosis. Through ErGPCR and Gα_q, 20E promotes Src family kinases to up-regulate the tyrosine phosphorylation of PLCG1 and induces the migration of phosphorylated PLCG1 toward the cell membrane to produce IP₃ and DAG. Then cytosolic calcium signals a fast increase, including the release of the intracellular Ca²⁺ and the influx of the extracellular Ca²⁺ via calcium channels (T-type calcium channels and/or TRP channels). The increased Ca²⁺ and DAG activate PKC to regulate the phosphorylation of USP1 and CDK10 for gene transcription and insect metamorphosis. This chart is based on the models reported by our laboratory, including the ErGPCR-regulated nongenomic action (15), the interaction between Hsc70 and USP1 (57), and the participation of CDK10-Hsp90-Hsc70-EcRB1 in the 20E transcriptional complex (14).