Activin receptor-like kinase(ALK)2 in human is located in 2q23-24, the intron is as long as 0.5-6.5 kb, and 3’ untranslated region has important function in regulatingALK2. ALK2 is conservatively consisted with extracellular domain, transmembrane domain, and intracellular domain which contains serine/threonine. ALK2, a member of bone morphogenetic protein(BMP) recepters can transduce cell signal which can be divided into canonical and non-canonical Smad signaling pathway. The ALK2-mediated canonical Smad signal has important function in regulating bone, cartilage, and tooth. ALK2 protein can be seen in various organs, including bone, cartilage, tooth, heart. ALK2 promotes bone formation in the early development stage of skull and inhibits bone formation in the maturation stage of development. It is known that mutant ofALK2 leads to ectopic bone formation which helps us understand the function of ALK2 in physical and pathological conditions.
