Domain

Pleiotrophin/Midkine disulphide-rich domain (IPR020091)

Short name: PTN/MK_diS

Domain relationships

Description

Several extracellular heparin-binding proteins involved in regulation of growth and differentiation belong to a new family of growth factors. These growth factors are highly related proteins of about 140 amino acids that contain 10 conserved cysteines probably involved in disulphide bonds, and include pleiotrophin [PMID: 15121180] (also known as heparin-binding growth-associated molecule HB-GAM, heparin-binding growth factor 8 HBGF-8, heparin-binding neutrophic factor HBNF and osteoblast specific protein OSF-1); midkine (MK) [PMID: 15047154]; retinoic acid-induced heparin-binding protein (RIHB) [PMID: 7796887]; and pleiotrophic factors alpha-1and -2 and beta-1 and -2 from Xenopus laevis, the homologues of midkine and pleiotrophin respectively. Pleiotrophin is a heparin-binding protein that has neurotrophic activity and has mitogenic activity towards fibroblasts. It is highly expressed in brain and uterus tissues, but is also found in gut, muscle and skin. It is thought to possess an important brain-specific function. Midkine is a regulator of differentiation whose expression is regulated by retinoic acid, and, like pleiotrophin, is a heparin-binding growth/differentiation factor that acts on fibroblasts and nerve cells.

Pleiotrophin is structurally divided into two domains, both domains consisting of three antiparallel beta-strands, but the C-terminal domain has a long flexible hairpin loop where a heparin-binding consensus sequence is located [PMID: 9384573]. This entry represents the all-beta 3 antiparallel strands disulfide-rich fold found both in the N-terminal and C-terminal domains of pleiotrophin and midkine.

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0008083 growth factor activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
SUPERFAMILY