Angiopoietin

Angiopoietins are growth factors that control the sprouting of blood vessels into tissue, known as angiogenesis . So far, four forms have been identified: Ang1, Ang2, Ang3, and Ang4.

In addition, there are proteins that are closely related to the angiopoietins: ANGPTL2, ANGPTL3, ANGPTL4. Ang1 and Ang2 are necessary for the formation of mature blood vessels, this has been shown in studies with knock-out mice. Angiopoietin 1 is released by the myocardium in early development and later by perivascular cells in adult tissue.

Angiopoietin receptors

Angiopoietin works by binding to the tyrosine kinase receptor Tie2 on endothelial cells. Tie receptors are endothelial-specific receptor tyrosine kinases .

Tie 1 in endothelial cell lines and leukemia cells
Tie 2 (tek) in heart tissue

The ligand to the receptors is angiopoietin, the receptor then triggers phosphorylation . After binding, it regulates the maturation of blood vessels during angiogenesis and controls the stability of the established vessels.

Overall, all types of angiopoietin (Ang1, Ang2, Ang3, Ang4) can bind to the Tie2 receptor, but only Ang1 triggers the phosphorylation. For this, Ang1 must be available as a tetramer . Ang2 can inhibit the phosphorylation triggered by Ang1.

Further literature

Barton WA, Tzvetkova D, Nikolov DB: Structure of the Angiopoietin-2 Receptor Binding Domain and Identification of Surfaces Involved in Tie2 Recognition . In: Structure . 13, May 2005, pp. 825-832. doi : 10.1016 / j.str.2005.03.009 . PMID 15893672 .
Felcht M, Luck R, Schering A, Seidel P, Srivastava K, Hu J, Bartol A, Kienast Y, Vettel C, Loos EK, Kutschera S, Bartels S, Appak S, Besemfelder E, Terhardt D, Chavakis E, Wieland T , Klein C, Thomas M, Uemura A, Goerdt S, Augustin HG: Angiopoietin-2 differentially regulates angiogenesis through TIE2 and integrin signaling . In: The Journal of clinical investigation . June 2012, p. 122 (6). doi : 10.1172 / JCI58832 . PMID 22585576 .

Web links

angiopoietin.de: endothelia activation from bench to bedside . Hannover Medical School. Retrieved June 27, 2012.

Individual evidence

↑ Thurston G: Role of Angiopoietins and Tie receptor tyrosine kinases in angiogenesis and lymphangiogenesis . In: Cell Tissue Res . 314, No. 1, October 2003, pp. 61-8. doi : 10.1007 / s00441-003-0749-6 . PMID 12915980 .
↑ Singh H, Tahir TA, Alawo DO, Issa E, Brindle NP: Molecular control of angiopoietin signaling . In: Biochem Soc Trans . 39, No. 6, December 2011. doi : 10.1042 / BST20110699 . PMID 22103492 .

[Thurston2003-1] Thurston G: Role of Angiopoietins and Tie receptor tyrosine kinases in angiogenesis and lymphangiogenesis . In: Cell Tissue Res . 314, No. 1, October 2003, pp. 61-8. doi : 10.1007 / s00441-003-0749-6 . PMID 12915980 .

[Singh2011-2] Singh H, Tahir TA, Alawo DO, Issa E, Brindle NP: Molecular control of angiopoietin signaling . In: Biochem Soc Trans . 39, No. 6, December 2011. doi : 10.1042 / BST20110699 . PMID 22103492 .