The angiopoietin receptors are receptors that bind
angiopoietin
Angiopoietin is part of a family of vascular growth factors that play a role in embryonic and postnatal angiogenesis. Angiopoietin signaling most directly corresponds with angiogenesis, the process by which new arteries and veins form from pree ...
.
TIE-1 and
TIE-2 comprise the cell-surface receptors that bind and are activated by the
angiopoietins, (Ang1, Ang2, Ang3, Ang4). The angiopoietins are protein growth factors required for the formation of blood vessels (
angiogenesis
Angiogenesis is the physiological process through which new blood vessels form from pre-existing vessels, formed in the earlier stage of vasculogenesis. Angiogenesis continues the growth of the vasculature by processes of sprouting and splitting ...
).
Angiopoietins
The
angiopoietins are
protein growth factors that regulate
angiogenesis
Angiogenesis is the physiological process through which new blood vessels form from pre-existing vessels, formed in the earlier stage of vasculogenesis. Angiogenesis continues the growth of the vasculature by processes of sprouting and splitting ...
, the formation of blood vessels. In humans, three angiopoietins have been identified: Ang1, Ang2, and Ang4 (Ang 3 is the mouse ortholog of human Ang4).
Ang1 and Ang4 function as agonistic or activating ligands for Tie2, whereas Ang2 and Ang3 behave as competitive antagonists. They function by binding their physiologic receptors, Tie-1 and Tie-2. These are receptor
tyrosine kinases, so named because they mediate cell signals by inducing the phosphorylation of key tyrosines, thus initiating
cell signalling
In biology, cell signaling (cell signalling in British English) or cell communication is the ability of a cell to receive, process, and transmit signals with its environment and with itself. Cell signaling is a fundamental property of all cellula ...
.
It is somewhat controversial which of the Tie receptors mediate functional signals downstream of Ang stimulation. But it is clear that at least Tie-2 is capable of physiologic activation as a result of binding the angiopoietins.
See also
*
Angiopoietin#Tie pathway
External links
*
References
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Tyrosine kinase receptors
Developmental neuroscience