GlyCosmos Portal

Submissions

Signaling by Erythropoietin

Summary

Organism

Homo sapiens (human)

Reactome

R-HSA-9006335

PubChem

R-HSA-9006335

Description

Erythropoietin (EPO) is a cytokine that serves as the primary regulator of erythropoiesis, the differentiation of erythrocytes from stem cells in the liver of the fetus and the bone marrow of adult mammals (reviewed in Ingley 2012, Zhang et al. 2014, Kuhrt and Wojchowski 2015). EPO is produced in the kidneys in response to low oxygen tension and binds a receptor, EPOR, located on progenitor cells: burst forming unit-erythroid (BFU-e) cells and colony forming unit-erythroid (CFU-e) cells.
The erythropoietin receptor (EPOR) exists in lipid rafts (reviewed in McGraw and List 2017) as a dimer pre-associated with proteins involved in downstream signaling: the tyrosine kinase JAK2, the tyrosine kinase LYN, and the scaffold protein IRS2. Binding of EPO to the EPOR dimer causes a change in conformation (reviewed in Watowich et al. 2011, Corbett et al. 2016) that activates JAK2, which then transphosphorylates JAK2 and phosphorylates the cytoplasmic domain of EPOR. The phosphorylated EPOR serves directly or indirectly as a docking site for signaling molecules such as STAT5, phosphatidylinositol 4,5-bisphosphate 3-kinase (PI3K), phospholipase C gamma (PLCG1, PLCG2), and activators of RAS (SHC1, GRB2:SOS1, GRB2:VAV1).
EPO activates 4 major signaling pathways: STAT5-activated transcription, PI3K-AKT, RAS-RAF-ERK, and PLC-PKC. JAK2-STAT5 activates expression of BCL2L1 (Bcl-xL) and therefore appears to be important for anti-apoptosis. PI3K-AKT appears to be important for both anti-apoptosis and proliferation. The roles of other signaling pathways are controversial but both RAS-RAF-MEK-ERK and PLCgamma-PKC have mitogenic effects. Phosphatases such as SHP1 are also recruited and downregulate the EPO signal.
EPO also has effects outside of erythropoiesis. The EPOR is expressed in various tissues such as endothelium where it can act to stimulate growth and promote cell survival (Debeljak et al. 2014, Kimáková et al. 2017). EPO and EPOR in the neurovascular system act via Akt, Wnt1, mTOR, SIRT1, and FOXO proteins to prevent apoptotic cell injury (reviewed in Ostrowski and Heinrich 2018, Maiese 2016) and EPO may have therapeutic value in the nervous system (Ma et al. 2016).

Click on a node on the pathway to see its details. Glycoproteins are marked with a glycoprotein icon in their name.

SPV: a JavaScript Signaling Pathway Visualizer, Bioinformatics, 2018

Displaying **all 3** entries
UniProt ID	Protein Name	Gene Symbol	Pathway Viewer
P01588	Erythropoietin	EPO	view
P19235	Erythropoietin receptor	EPOR	view
Q9Y4H2	Insulin receptor substrate 2	IRS2	view

If you want to check the location of a particular molecule, you can do so by clicking on the "Switching Highlight" button on the page you have navigated to by clicking on "view".

About Release Notes Help Feedback

Click here to visit the beta site.