Protein jagged-1 (JAG1) is also known as Jagged1, hJ1, JAGL1 and CD339, which is a single-pass type I membrane protein containing one DSL domain and 15 EGF-like domains. JAG1 is widely expressed in adult and fetal tissues,the expression of JAG1 is up-regulated in cervical squamous cell carcinoma and also expressed in bone marrow cell line HS-27a.JAG1 is a ligand for multiple Notch receptors and involved in the mediation of Notch signaling. JAG1 is involved in early and late stages of mammalian cardiovascular development. JAG1 inhibits myoblast differentiation by similarity and enhances fibroblast growth factor-induced angiogenesis (in vitro).