PTN (pleiotrophin) is a 136-residue, platelet-derived growth factor (PDGF)-inducible, heparin-binding cytokine. It shares ~50% similarity with midkine, a retinoic acid-inducible factor. It is expressed in a tissue and stage dependent manner during development, but in adults, this protein is expressed constitutively, though in a restricted tissue pattern. PTN is a low molecular weight protein composed of two domains linked by disulfide bridges, with three antiparallel β-sheets in each domain. This gene is localized to human chromosome 7q33-q34. Recombinant human Pleiotrophin is a 15.4 kDa protein containing 136 amino acid residues and five intra-molecular disulfide bonds.

PTN (pleiotrophin) is a ligand for receptor protein tyrosine phosphatase (RPTP) β/ζ, and binds with it and inhibits its catalytic capabilities in a “ligand-dependent receptor inactivation”-mechanism, and promotes tyrosine phosphorylation of β-catenin. It acts as a mitogen for fibroblasts, endothelial cells, epithelial cells, and trophoblasts. It promotes neurite outgrowth and glial process outgrowth from neurons and glial progenitor cells, respectively. This protein functions as a protooncogene, and is up-regulated in multiple types of tumors, where it promotes tumor angiogenesis and progression. This protein functions as a crucial mitogen during nerve, bone, vascular, and tumor growth, and has been found to be up-regulated in macrodactyly, identifying it as a candidate gene for macrodactyly.

GKKEKPEKKV KKSDCGEWQW SVCVPTSGDC GLGTREGTRT GAECKQTMKT QRCKIPCNWK KQFGAECKYQ FQAWGECDLN TALKTRTGSL KRALHNAECQ KTVTISKPCG KLTKPKPQAE SKKKKKEGKK QEKMLD

Lyophilized from 10 mM sodium phosphate, pH 7.5.

Centrifuge the vial prior to opening. Reconstitute in water to a concentration of 0.1-1.0 mg/ml. Do not vortex. This solution can be stored at 2-8°C for up to 1 week. For extended storage, it is recommended to further dilute in a buffer containing a carrier protein (example 0.1% BSA) and store in working aliquots at -20°C to -80°C.