TIE 2 or TEK is a receptor tyrosine kinase that is expressed principally on vascular endothelium. Disrupting TIE 2 function in mice results in embryonic lethality with defects in embryonic vasculature, suggesting a role in blood vessel maturation and maintenance. Angiopoietin-1 is a secreted growth factor that binds to and activates the TIE 2 receptor tyrosine kinase. SHP2 and GRB2 are recruited to the activated TIE 2 kinase domain and are part of the cellular responses that mediate TIE 2 function. TIE 2 expression is upregulated in the endothelium of vascular "hot spots" in human breast cancer specimens. However, TIE 2 is also overexpressed in areas of active angiogenesis in normal tissues.
General Description
The TEK receptor tyrosine kinase is expressed almost exclusively in endothelial cells in mice, rats, and humans. This receptor possesses a unique extracellular domain containing 2 immunoglobulin-like loops separated by 3 epidermal growth factor-like repeats that are connected to 3 fibronectin type III-like repeats. The ligand for the receptor is angiopoietin-1. Defects in TEK are associated with inherited venous malformations; the TEK signaling pathway appears to be critical for endothelial cell-smooth muscle cell communication in venous morphogenesis. TEK is closely related to the TIE receptor tyrosine kinase. (provided by RefSeq)
