Thrombopoietin

Thrombopoietin is a prime and physiologic regulator of megakaryopoiesis (megakaryocytopoiesis) and platelet production. A glycoprotein binds to its receptor MPL (c-Mpl or TPO receptor) on the surface of megakaryocyte progenitors to stimulate proliferation and differentiation toward mature megakaryocytes with a higher ploidy class that acquires the capacity for platelet shedding, and maintains hematopoietic stem cells. It is predominantly produced in the liver constitutively and in the bone marrow microenvironment inductively. Other nonhematopoietic roles such as antiapoptotic effects in various cells are reported.