Protein tyrosine phosphatase receptor type

The identification of basophil cells was initially based on the presence of the high affinity receptor for immunoglobulin E and expression of CD45 or protein tyrosine phosphatase receptor type C (PTPRC) also known as leukocyte common antigen, a FTP signaling molecule found on all leukocytes. To distinguish basophils from other leukocyte populations, a number of selection strategies are possible. One procedure... 

Krasnoperov VG, Beavis R, Chepumy OG et al (1996) The calcium-independent receptor of a-latrotoxin is not a neurexin. Biochem Biophys Res Commun 227 868-75 Krasnoperov VG, Bittner MA, Beavis R et al (1997) a-Latrotoxin stimulates exocytosis by the interaction with a neuronal G-protein-coupled receptor. Neuron 18 925-37 Krasnoperov VG, Bittner MA, Mo W et al (2002b) Protein tyrosine phosphatase-G is a novel member of the functional family of a-latrotoxin receptors. J Biol Chem 277 35887-95 Kreienkamp HJ, Zitzer H, Gundelfinger ED et al (2000) The calcium-independent receptor for a-latrotoxin from human and rodent brains interacts with members of the ProSAP/SSTRIP/Shank family of multidomain proteins. J Biol Chem 275 32387-90 Lajus S, Lang J (2006) Splice variant 3, but not 2 of receptor protein-tyrosine phosphatase a can mediate stimulation of insulin-secretion by a-latrotoxin. J Cell Biochem 98 1552-9 Lajus S, Vacher P, Huber D et al (2006) a-Latrotoxin induces exocytosis by inhibition of voltage-dependent K+ channels and by stimulation of L-type Ca2+ channels via latrophilin in [5-cells. J Biol Chem 281 5522-31... 

L., Margolis, R.K., Grumet, M. and Margolis, R.U. (1994) Interactions of the chondroitin sulfate proteoglycan phosphacan, the extracellular domain of a receptor-type protein tyrosin phosphatase, with neurons, glia, and neural cell adhesion molecules. J. Cell Biol. 127 1703-1715. 

When feeding has finished, insulin secretion stops and insulin signal transduction within the cell must be terminated. Dephosphorylation of the insulin receptor by protein tyrosine phosphatase (PTPase) occurs, which inactivates the insulin receptor and insulin signalling ceases. However, there is evidence that some diabetic patients have a form of PTPase that is inappropriately active and opposes normal activation of the receptor by phosphorylation. Currently, there is a major research effort to develop drugs that inhibit PTPase and provide a new treatment for type 2 diabetes. 

CLP also attracted attention in type II diabetes and obesity-related research. CLP inhibited human protein tyrosine phosphatase IB (hPTPlB) which can hydrolyze phosphotyrosines on the insulin receptor and deactivates it [59]. 

Bedecs, K., Elbaz, N., Sutren, M., Masson, M., Susini, C., Strosberg, A.D., and Nahmias, C. 1997. Angiotensin II type 2 receptors mediate inhibition of mitogen-activated protein kinase cascade and functional activation of SHP-1 tyrosine phosphatase. Biochem. J. 325 449-454. 

Part-time extracellular proteoglycans include variants of well-characterized extracellular glycoproteins such as type IX collagen [141], Clq [142], colony stimulating factor [143], amyloid precursor protein [144], fibronectin [145], and brain-specific receptor-type tyrosine phosphatase (3 [146]. 

The disturbances in protein phosphorylation patterns in Cr(VI) treated cells are considered among the possible reasons for Cr(VI) toxicity and carcinogenicity (295, 626). The question then arises, as to whether the proposed beneficial action of Cr(III) in activation of insulin receptor tyrosine kinase (496,497) is, in fact, a sign of Cr(III) toxicity (5). Unpredictable changes in the concentrations of phosphorylated proteins in the presence of excess Cr(III) may lead to abnormalities in the cell signaling pathways and ultimately to cancer (5). An answer to this dilemma may lie in selectivity studies (which are yet to be performed) of different types of Cr(III) complexes toward various kinases or phosphatases. Clearly, the Cr(III) complexes of potential use as anti-diabetics should be highly selective in the activation of protein tyrosine kinase of the p-subunit of the insulin receptor (496, 497). On the other hand, the potential ability of some Cr(III) complexes to selectively activate non-insulin dependent protein kinases may lead to beneficial effects, such as stimulation of immune responses or antitumor activity (627, 628). 

Krndija, D., H. Schmid, J.L. Eismann, U. Lother, G. Adler, F. Oswald, T. Seufferlein, and G. Von Wichert. 2010. Substrate stiffness and the receptor-type tyrosine-protein phosphatase alpha regulate spreading of colon cancer cells through cytoskeletal contractility. Oncogene 29(18) 2724-38. 

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