Bone homeostasis, including bone resorption and bone formation, is a delicate and important process with various molecules coordinating osteoclast function with that of osteoblasts. Nowadays more and more re - searchers focus on the effects of bidirectional signal transduciton between erythropoietin producing hepatocyte kinases（Eph） and erythropoietin producing hepatocyte kinases receptor interacting protein（ephrin） ligands in bone homeostasis. Our article illustrates the bidirectional signal transduction of Eph/ephrin in different stages in bone remodeling.
