※ Tie family introduction

    Tie family belong to the receptor tyrosine kinase. Two members have been found in human genome, Tie1 and Tie2. Sequence analysis show that Tie kinases contain an extracellular region which consists of two immunoglobulin(lg)-like domains with one incomplete, the two lg-like domains are separated by three EGF-like cysteine repeats, three fibronectin type III homology domains locate proximally to membrane. The intracellular region contains the tyrosine protein kinase domains (1). Tie1 and Tie2 play an important role on regulation of endothelial cell proliferation, migration and survival during angiogensis. Tie2 has also been found to be involved in vascular abnormalities. In addition, Tie2 can maintain the hematopoietic stem cells's population and quiescent status. Tie2 is also associated with several cancers and overexpression has been identified in tumoral vessels (2).

Reference
1. Jones, N., Iljin, K., Dumont, D.J. and Alitalo, K. (2001) Tie receptors: new modulators of angiogenic and lymphangiogenic responses. Nat Rev Mol Cell Biol, 2, 257-267. PMID: 11283723
2. Martin, V., Liu, D., Fueyo, J. and Gomez-Manzano, C. (2008) Tie2: a journey from normal angiogenesis to cancer and beyond. Histol Histopathol, 23, 773-780. PMID: 18366015