 The two receptor pathways are named as a result of their role in mediating cell signals by inducing the phosphorylation of specific tyrosines.This in turn initiates the binding and activation of downstream intracellular enzymes, a process known as cell signaling.Tie-2/Ang-1 signaling activates β1-integrin and N-cadherin in LSK-Tie2+ cells and promotes hematopoietic stem cell (HSC) interactions with extracellular matrix and its cellular components.