title: Consensus substrate sequence for protein-tyrosine phosphatase receptor type Z.
abstract: Protein-tyrosine phosphatase receptor type Z (Ptprz) has multiple substrate proteins, including G protein-coupled receptor kinase-interactor 1 (Git1), membrane-associated guanylate kinase, WW and PDZ domain-containing 1 (Magi1), and GTPase-activating protein for Rho GTPase (p190RhoGAP). We have identified a dephosphorylation site at Tyr-1105 of p190RhoGAP; however, the structural determinants employed for substrate recognition of Ptprz have not been fully defined. In the present study, we revealed that Ptprz selectively dephosphorylates Git1 at Tyr-554, and Magi1 at Tyr-373 and Tyr-858 by in vitro and cell-based assays. Of note, the dephosphorylation of the Magi1 Tyr-858 site required PDZ domain-mediated interaction between Magi1 and Ptprz in the cellular context. Alignment of the primary sequences surrounding the target phosphotyrosine residue in these three substrates showed considerable similarity, suggesting a consensus motif for recognition by Ptprz. We then estimated the contribution of surrounding individual amino acid side chains to the catalytic efficiency by using fluorescent peptides based on the Git1 Tyr-554 sequence in vitro. The typical substrate motif for the catalytic domain of Ptprz was deduced to be Glu/Asp-Glu/Asp-Glu/Asp-Xaa-Ile/Val-Tyr(P)-Xaa (Xaa is not an acidic residue). Intriguingly, a G854D substitution of the Magi1 Tyr-858 site matching better to the motif sequence turned this site to be susceptible to dephosphorylation by Ptprz independent of the PDZ domain-mediated interaction in cells. Furthermore, we found by database screening that the substrate motif is present in several proteins, including paxillin at Tyr-118, its major phosphorylation site. Expectedly, we verified that Ptprz efficiently dephosphorylates paxillin at this site in cells. Our study thus provides key insights into the molecular basis for the substrate recognition of Ptprz.
authors: Division of Molecular Neurobiology, National Institute for Basic Biology, The Graduate University for Advanced Studies, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan.
authors: Akihiro
authors: A
authors: Fujikawa
authors: Masahide
authors: M
authors: Fukada
authors: Yoshikazu
authors: Y
authors: Makioka
authors: Ryoko
authors: R
authors: Suzuki
authors: Jeremy Pak Hong
authors: JP
authors: Chow
authors: Masahito
authors: M
authors: Matsumoto
authors: Masaharu
authors: M
authors: Noda
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020816:Amino Acid Motifs; D000818:Animals; D015815:Cell Adhesion Molecules; D015816:Cell Adhesion Molecules, Neuronal / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051528:Guanylate Kinases; D057809:HEK293 Cells; D006801:Humans; D051419:Paxillin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010750:Phosphoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D051381:Rats; D054633:Receptor-Like Protein Tyrosine Phosphatases, Class 5 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D015815:Cell Adhesion Molecules; D015816:Cell Adhesion Molecules, Neuronal; D018797:Cell Cycle Proteins; C485647:GIT1 protein, human; C485648:Git1 protein, rat; C496061:PXN protein, human; D051419:Paxillin; D010750:Phosphoproteins; C496063:Pxn protein, rat; D051528:Guanylate Kinases; C113338:MAGI1 protein, human; D054633:Receptor-Like Protein Tyrosine Phosphatases, Class 5