Ephrin receptors and Ephrins are both membrane bound, and following their interaction and clustering, each can transduce signals that regulate cell responses [1].

Chemokine (C-X-C motif) receptor-4 (CXCR4) is a G protein-coupled receptor (GPCR). It is the only known receptor for stromal-derived factor-1 (SDF-1), and SDF-1 is the only known ligand for CXCR4 [1].

The binding of Plasminogen activator, urokinase (PLAU (UPA)) to its glycosyl-phosphatidyl-inositol (GPI) anchored Plasminogen activator, urokinase receptor (PLAUR (UPAR) (uPAR)) mediates a variety of functions including vascular homeostasis, inflammation and tissue repair [1].