Purification and cloning of PZR, a binding protein and putative physiological substrate of tyrosine phosphatase SHP-2.
Overexpression of a catalytically inactive mutant of tyrosine phosphatase SHP-2 in 293 cells resulted in hyperphosphorylation of a glycoprotein specifically associated with the enzyme. The protein has been purified to near homogeneity. Based on the amino acid sequences of peptides obtained from the protein, a full-length cDNA was isolated. The cDNA encodes a protein with a single transmembrane segment and a signal sequence. The extracellular portion of the protein contains a single immunoglobulin-like domain displaying 46% sequence identity to that of myelin P0, a major structural protein of peripheral myelin. The intracellular segment of the protein shows no significant sequence identity to any known protein except for two immunoreceptor tyrosine-based inhibitory motifs. We name the protein PZR for protein zero related. Transfection of the PZR cDNA in Jurkat cells gave rise to a protein of expected molecular size. Stimulation of cells with pervanadate resulted in tyrosine phosphorylation of PZR and a near-stoichiometric association of PZR with SHP-2. Northern blotting analyses revealed that PZR is widely expressed in human tissues and is particularly abundant in heart, placenta, kidney, and pancreas. As a binding protein and a putative substrate of SHP-2, PZR protein may have an important role in cell signaling.
Pubmed ID: 9792637 RIS Download
Amino Acid Sequence | Base Sequence | Blotting, Northern | Carrier Proteins | Cell Line | Chromatography, High Pressure Liquid | Cloning, Molecular | DNA, Complementary | Humans | Intracellular Signaling Peptides and Proteins | Molecular Sequence Data | Phosphoproteins | Precipitin Tests | Protein Tyrosine Phosphatase, Non-Receptor Type 11 | Protein Tyrosine Phosphatase, Non-Receptor Type 6 | Protein Tyrosine Phosphatases | Sequence Homology, Amino Acid | Substrate Specificity