Activation of the TPO receptor

The TPO receptor has been proposed to exist as an inactive preformed dimer (left side) with a proximal and distal hematopoietic receptor domain (HRD) (HRD-1 and HRD-2, respectively). Upon binding of TPO to the distal HRD-2, the conformation of the receptor changes (right side) and a number of signal transduction pathways are activated that increase platelet production.