title: The tyrosine phosphatase HD-PTP (PTPN23) is degraded by calpains in a calcium-dependent manner.
abstract: HD-PTP (PTPN23) is a non-transmembrane protein tyrosine phosphatase which contributes to the signal transduction pathways involved in the regulation of cell migration and invasion. We here demonstrate in T24 bladder carcinoma cells that HD-PTP undergoes calcium-dependent degradation which can be prevented by specific calpain inhibitors. In addition, treatment of the cells with the calpain inhibitor calpeptin results in the redistribution of endogenous HD-PTP to the periphery of the cells. Since (i) calpains are overexpressed in some tumors and (ii) the downregulation of HD-PTP enhances cell migration and invasion, we propose that HD-PTP degradation by calpains might result in the acquisition of a more aggressive phenotype in neoplastic cells.
authors.affiliation: Department of Clinical Sciences L. Sacco, Università di Milano, Via GB Grassi, 74 Milano, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Castiglioni
authors.forename: Jeanette A M
authors.initials: JA
authors.lastname: Maier
mesh_terms: D002118:Calcium / Q000378:metabolism*; D002154:Calpain / Q000037:antagonists & inhibitors / Q000378:metabolism*; D045744:Cell Line, Tumor; D002465:Cell Movement; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004151:Dipeptides / Q000494:pharmacology; D006801:Humans; D009361:Neoplasm Invasiveness; D054558:Protein Tyrosine Phosphatases, Non-Receptor / Q000378:metabolism*; D059748:Proteolysis
chemical_list: D015853:Cysteine Proteinase Inhibitors; D004151:Dipeptides; C071482:calpeptin; C114102:PTPN23 protein, human; D054558:Protein Tyrosine Phosphatases, Non-Receptor; D002154:Calpain; D002118:Calcium