Therefore further investigation is required to fully understand the EPOR heterodimer isoform, and the mechanisms and pathways involved in its tissue protective activity.
As mentioned, it is uncertain whether the pathways for tissue-protection are activated by EPOR homodimers or heterodimers, both, or another receptor conformation (18).
Indeed, inhibition of protein kinase C activity interferes with phosphorylation of the EPOR which suggests that protein kinase C may be an upstream modulator of the EPOR (27).
It appears that angiogenesis is impaired and blood vessels are less responsive to VEGF in the absence of EPOR.
Human neurons, astrocytes and microglial cells produce EPO and express EPOR (54).
Half life is too short for erythropoiesis as continuous EPOR stimulation is required.
This form has a very short plasma half-life and possesses the same high affinity for EPOR as rhEPO.
This analogue does not bind to the classical EPOR, but instead engages an alternative receptor that then signals tissue protection (Leist et al., 2004).
EPO and EPOR are expressed in the cerebral cortex, cerebellum, hippocampus, pituitary gland, and spinal cord (Jelkmann, 2005).
Furthermore, abundant expression of EPOR protein has also been found in macrophages, cells that play a pivotal role during wound healing (Haroon et al., 2003).
(2008) examined the protein expression of EPO and EPOR, STAT5, and pro-apoptotic protein Bcl-2-associated X (BAX) across various developmental stages of retinal neuron and lens cell differentiation during eye development.
However, they also observed that EPOR expression was similar in both groups.