Erythropoiesis: Cellular and Molecular Implications

Hematopoiesis is a dynamic process resulting in continuous production of mature blood cells, from a small population of pluripotent stem cells through several proliferative and differentiative events. Different functions of hematopoietic cells are regulated by growth factors and cytokines, and by the interaction with other cells and extracellular matrix.

Erythropoiesis is mainly orchestrated by erythropoietin and its receptor. Binding of this growth factor to its receptor induces the activation of signal transduction intermediates, especially the JAK2/STAT5 (Janus associated kinase 2/signal transducers and activators of transcription 5), the mitogen activated protein (MAP) kinase and the phosphatidylinositol 3 (PI3) kinase pathways. Several transcription factors are then activated, which will initiate transcription of specific genes. Embryonic and adult erythropoiesis require broad spectrum transcription factors, as well as, specific erythroid transcription factors, which are necessary for the regulation of cell cycle, cell survival, differentiation, proliferation and for the intermediary metabolism of cells and to block apoptosis.

Keywords: Growth factors, growth factors receptors, signal transduction, transcription factors.