PTPRs, Recombinant, Human (Protein Tyrosine Phosphatase Receptor-type Sigma, PTPRS)

Phosphatase Receptor-type sigma (PTPRs), also known as PTPs, is a 200kD type I transmembrane glycoprotein that is a member of the class 2A (LAR) subfamily of the protein tyrosine phosphatase (PTP) family (1). Human PTPRs cDNA encodes 1948aa including a 29aa signal sequence, a 1253aa extracellular domain (ECD) with three C2-type Ig domains and eight Fibronectin (Fn) type III domains, a transmembrane domain, and a cytoplasmic region with two PTP domains (1, 2). Multiple differentially expressed splice variants lack sections of the Ig and/or Fn domains and/or cytoplasmic juxtamembrane sequence (1, 2). PKC activation in the cell promotes endoprotease cleavage of PTPRs, releasing the 140-160kD ECD (3). The human PTPRs ECD shares 93%aa sequence identity with the nearest isoform of mouse and rat PTPRs, 96% with bovine PTPRs, and 97% with porcine PTPRs. Activity of PTPRs can be inhibited by bisphosphonates (2). PTPRs is a receptor for several proteins, including neural chondroitin sulfate proteoglycans which inhibit nerve regeneration (4, 5). It also binds and dephosphorylates targets such as N-Cadherin, E-Cadherin, EGF R and Ret (6-9). Through these interactions PTPRs affects pituitary and neuroendocrine development, and axon growth and targeting (4-6). Mice deleted for PTPRs show pituitary, pancreatic, and gut abnormalities, mainly due to growth hormone insufficiency (9-12). They also show enhanced regeneration, but faulty targeting, of injured peripheral nerves (4-6, 13). Head and neck squamous cell cancers frequently underexpress PTPRs (14). Since PTPRs inhibits EGF R signaling pathways, its underexpression can enhance tumor cell growth (14). Source: Recombinant corresponding to aa30-1260 from human PTPRs at C-terminal, fused to 6-His tag expressed in NS0 cells (NP_570924). Molecular Weight: ~135.8kD Biological Activity: Measured by its binding ability in a functional ELISA. When Recombinant Human PTPR sigma is coated at 2ug/ml, rhTrkC Fc Chimera binds with KD <1nm. Endotoxin: <0.10 EU per 1ug of protein by the LAL method Storage and Stability: Lyophilized powder may be stored at -20 degrees C. Stable for 12 months at -20 degrees C. Reconstitute with sterile buffer or ddH2O. Aliquot to avoid repeated freezing and thawing. Store at -20 degrees C. Reconstituted product is stable for 6 months at -20 degrees C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.