FunctionNeuroendocrine peptide which is a critical regulator of cellular and organ growth, development, migration, differentiation and survival and of epithelial calcium ion transport. Regulates endochondral bone development and epithelial-mesenchymal interactions during the formation of the mammary glands and teeth. Required for skeletal homeostasis. Promotes mammary mesenchyme differentiation and bud outgrowth by modulating mesenchymal cell responsiveness to BMPs. Upregulates BMPR1A expression in the mammary mesenchyme and this increases the sensitivity of these cells to BMPs and allows them to respond to BMP4 in a paracrine and/or autocrine fashion. BMP4 signaling in the mesenchyme, in turn, triggers epithelial outgrowth and augments MSX2 expression, which causes the mammary mesenchyme to inhibit hair follicle formation within the nipple sheath (By similarity). Promotes colon cancer cell migration and invasion in an integrin alpha-6/beta-1-dependent manner through activation of Rac1. Osteostatin is a potent inhibitor of osteoclastic bone resorption.
Tissue specificityUbiquitous. Also expressed in the mammary gland.
Involvement in diseaseDefects in PTHLH are the cause of brachydactyly type E2 (BDE2) [MIM:613382]. BDE2 is a form of brachydactyly. Brachydactyly defines a group of inherited malformations characterized by shortening of the digits due to abnormal development of the phalanges and/or the metacarpals. Brachydactyly type E is characterized by shortening of the fingers mainly in the metacarpals and metatarsals. Wide variability in the number of digits affected occurs from person to person, even in the same family. Some individuals are moderately short of stature. In brachydactyly type E2 variable combinations of metacarpals are involved, with shortening also of the first and third distal and the second and fifth middle phalanges.
Sequence similaritiesBelongs to the parathyroid hormone family.
Post-translational modificationsThere are 3 principal secretory forms, called PTHrP[1-36], PTHrP[38-94], and osteostatin (PTHrP[107-139]) arising from endoproteolytic cleavage of the initial translation product. Each of these secretory forms is believed to have one or more of its own receptors that mediates the normal paracrine, autocrine and endocrine actions.