CD136
CD136 is the RON receptor tyrosine kinase, the product of the MST1R gene and the closest relative of the MET/HGF receptor. Its ligand is macrophage-stimulating protein (MSP), a serum zymogen activated by proteolytic cleavage at sites of tissue injury. RON signaling through its multifunctional docking site activates MAPK, PI3K and STAT3, promoting macrophage activation, epithelial wound healing and epithelial-mesenchymal plasticity. It is expressed mainly on macrophages, dendritic cells and epithelial cells of skin, gut and kidney, as well as on a number of carcinomas. Ligand-dependent splice variants and overexpression have been implicated in tumor progression, and RON antagonists are being developed as cancer therapeutics.
