Figure 2.

TSH action. Binding of TSH to the TSHR results in activation of G protein-coupled downstream signaling including: 1) the adenylyl cyclase (AC), cAMP, protein kinase A (PKA), and the cAMP response element binding (CREB) protein; or 2) phospholipase C (PLC), inositol triphosphate (IP₃), and intracellular calcium pathway; or 3) the PLC, diacylglycerol (DAG), protein kinase C (PKC), and signal transducer and activator of transcription 3 (STAT3) pathway. PIP₂, phosphatidylinositol 4,5-bisphosphate.