Tie-1 receptor tyrosine kinase endodomain interaction with SHP2: potential signalling mechanisms and roles in angiogenesis.
The endothelial receptor tyrosine kinase plays an essential role in vascular development where it is thought to be required for vessel maturation and stabilization. The ligands responsible for activating Tie-1, its signalling pathways and specific cellular functions are however not known. As with some other receptor tyrosine kinases, Tie-1 is subject to extracellular proteolytic cleavage generating a membrane bound receptor fragment comprising the intracellular and transmembrane domains. Here we examine the signalling potential of this Tie-1 endodomain. We show that the Tie-1 endodomain has poor ability to induce tyrosine phosphorylation. However, on formation the endodomain physically associates with a number of tyrosine phosphorylated signalling intermediates including the tyrosine phosphatase and adaptor protein SHP2. The assembly of this multimolecular complex is consistent with the endodomain having a ligand-independent signalling role in the endothelial cell. The potential roles of ectodomain cleavage and cleavage activated signalling in regulating microvessel stability in angiogenesis, vessel remodelling and regression are considered.
Marron
M B
MB
University of Leicester Cardiovascular Research Institute, UK.
Hughes
D P
DP
McCarthy
M J
MJ
Beaumont
E R
ER
Brindle
N P
NP
D000818:Animals; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D018919:Neovascularization, Physiologic / Q000502:physiology*; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism / Q000502:physiology*; D042810:Receptor, TIE-1; D011956:Receptors, Cell Surface / Q000378:metabolism / Q000502:physiology*; D042764:Receptors, TIE; D015398:Signal Transduction / Q000502:physiology*
D047908:Intracellular Signaling Peptides and Proteins; D011956:Receptors, Cell Surface; D020794:Receptor Protein-Tyrosine Kinases; D042810:Receptor, TIE-1; D042764:Receptors, TIE; C516724:PTPN11 protein, human; C509249:PTPN6 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases