scholarly journals The receptor PTPRU is a redox sensitive pseudophosphatase

2019 ◽  
Author(s):  
Iain M. Hay ◽  
Gareth W. Fearnley ◽  
Pablo Rios ◽  
Maja Köhn ◽  
Hayley J. Sharpe ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Cell Adhesion ◽  
Tyrosine Phosphorylation ◽  
Catalytic Mechanism ◽  
Protein Tyrosine Phosphatases ◽  
Protein Tyrosine Phosphorylation ◽  
Tyrosine Phosphatases ◽  
Post Translational Modification ◽  
Critical Feature ◽  
Protein Tyrosine

ABSTRACTThe dynamic regulation of protein tyrosine phosphorylation is a critical feature of intercellular communication and is regulated by the actions of kinases and phosphatases. The receptor-linked protein tyrosine phosphatases (RPTPs) are key signaling molecules that possess an extracellular domain and intracellular phosphatase domains. Most human RPTPs have tandem intracellular tyrosine phosphatase domains: a catalytically active membrane proximal (D1) domain; and a membrane distal (D2) inactive “pseudophosphatase” domain. The receptor PTPRU plays a role in development, multiple cancers and has been implicated in the dephosphorylation of cell adhesion proteins. However, PTPRU has a non-canonical D1 domain containing several sequence variations in key catalytic loops that suggest it may function using a mechanism distinct from related RPTPs. Here, we demonstrate through biochemical and structural studies that PTPRU is unique amongst the RPTPs in possessing two pseudophosphatase domains. We show that PTPRU-D1 displays no detectable catalytic activity against a range of phosphorylated substrates and determine that this is due to substantial disorder in the substrate-binding pocket as well as rearrangement of the catalytic loop such that the active site cysteine is occluded. We also show that this cysteine can form an intramolecular disulfide bond with a vicinal “backdoor” cysteine. Further, we demonstrate that the PTPRU D2 domain can recruit substrates of related RPTPs suggesting that this pseudophosphatase functions by competing with active phosphatases for the binding of substrates involved in cell adhesion. Therefore, PTPRU is a bona-fide pseudophosphatase and its functional role in cell signaling is via a non-catalytic mechanism.SIGNIFICANCE STATEMENTProtein tyrosine phosphorylation is a key post-translational modification required for cellular communication that is dynamically regulated by the activities of tyrosine kinases and phosphatases. Receptor tyrosine phosphatases (RPTPs) possess an extracellular receptor domain and intracellular phosphatase domains. We show that PTPRU is a non-canonical RPTP devoid of catalytic activity and demonstrate that this is due to multiple structural rearrangements. Despite this, PTPRU retains the capacity to bind the substrates of related phosphatases suggesting that the non-catalytic function of this pseudophosphatase is to compete with active phosphatases for the binding of substrates. Such pseudoenzymes represent an exciting and growing area of research with implications as key regulators of signaling networks.

scholarly journals Protein tyrosine phosphatase containing SH2 domains: characterization, preferential expression in hematopoietic cells, and localization to human chromosome 12p12-p13.

1992 ◽  
Vol 12 (2) ◽  
pp. 836-846 ◽  
Author(s):  
T L Yi ◽  
J L Cleveland ◽  
J N Ihle
Keyword(s):  
Tyrosine Phosphorylation ◽  
Protein Tyrosine Phosphatase ◽  
Human Gene ◽  
Tyrosine Phosphatase ◽  
Hematopoietic Cells ◽  
Protein Tyrosine Phosphatases ◽  
Hematopoietic Cell ◽  
Protein Tyrosine Phosphorylation ◽  
Tyrosine Phosphatases ◽  
Protein Tyrosine

Protein tyrosine phosphorylation has been implicated in the growth and functional responses of hematopoietic cells. Recently, approaches have been developed to characterize the protein tyrosine phosphatases that may contribute to regulation of protein tyrosine phosphorylation. One novel protein tyrosine phosphatase was expressed predominantly in hematopoietic cells. Hematopoietic cell phosphatase encodes a 68-kDa protein that contains a single phosphatase conserved domain. Unlike other known protein tyrosine phosphatases, hematopoietic cell phosphatase contains two src homology 2 domains. We also cloned the human homolog, which has 95% amino acid sequence identity. Both the murine and human gene products have tyrosine-specific phosphatase activity, and both are expressed predominantly in hematopoietic cells. Importantly, the human gene maps to chromosome 12 region p12-p13. This region is associated with rearrangements in approximately 10% of cases of acute lymphocytic leukemia in children.

Protein tyrosine phosphatase containing SH2 domains: characterization, preferential expression in hematopoietic cells, and localization to human chromosome 12p12-p13

1992 ◽  
Vol 12 (2) ◽  
pp. 836-846
Author(s):  
T L Yi ◽  
J L Cleveland ◽  
J N Ihle
Keyword(s):  
Tyrosine Phosphorylation ◽  
Protein Tyrosine Phosphatase ◽  
Human Gene ◽  
Tyrosine Phosphatase ◽  
Hematopoietic Cells ◽  
Protein Tyrosine Phosphatases ◽  
Hematopoietic Cell ◽  
Protein Tyrosine Phosphorylation ◽  
Tyrosine Phosphatases ◽  
Protein Tyrosine

Protein tyrosine phosphorylation has been implicated in the growth and functional responses of hematopoietic cells. Recently, approaches have been developed to characterize the protein tyrosine phosphatases that may contribute to regulation of protein tyrosine phosphorylation. One novel protein tyrosine phosphatase was expressed predominantly in hematopoietic cells. Hematopoietic cell phosphatase encodes a 68-kDa protein that contains a single phosphatase conserved domain. Unlike other known protein tyrosine phosphatases, hematopoietic cell phosphatase contains two src homology 2 domains. We also cloned the human homolog, which has 95% amino acid sequence identity. Both the murine and human gene products have tyrosine-specific phosphatase activity, and both are expressed predominantly in hematopoietic cells. Importantly, the human gene maps to chromosome 12 region p12-p13. This region is associated with rearrangements in approximately 10% of cases of acute lymphocytic leukemia in children.

scholarly journals SHP1 and SHP2 Protein-tyrosine Phosphatases Associate with βc after Interleukin-3-induced Receptor Tyrosine Phosphorylation

1997 ◽  
Vol 272 (22) ◽  
pp. 14470-14476 ◽  
Author(s):  
Heather Bone ◽  
Ute Dechert ◽  
Frank Jirik ◽  
John W. Schrader ◽  
Melanie J. Welham
Keyword(s):  
Tyrosine Phosphorylation ◽  
Protein Tyrosine Phosphatases ◽  
Tyrosine Phosphatases ◽  
Protein Tyrosine ◽  
Interleukin 3

scholarly journals Podocyte Protein, Nephrin, Is a Substrate of Protein Tyrosine Phosphatase 1B

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Lamine Aoudjit ◽  
Ruihua Jiang ◽  
Tae Hoon Lee ◽  
Laura A. New ◽  
Nina Jones ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Tyrosine Phosphorylation ◽  
Tyrosine Phosphatase ◽  
Protein Tyrosine Phosphatases ◽  
Protein Tyrosine Phosphatase 1B ◽  
Tyrosine Phosphatases ◽  
Puromycin Aminonucleoside ◽  
Protein Tyrosine ◽  
Aminonucleoside Nephrosis ◽  
Puromycin Aminonucleoside Nephrosis

Glomerular podocytes are critical for the barrier function of the glomerulus in the kidney and their dysfunction causes protein leakage into the urine (proteinuria). Nephrin is a key podocyte protein, which regulates the actin cytoskeleton via tyrosine phosphorylation of its cytoplasmic domain. Here we report that two protein tyrosine phosphatases, PTP1B and PTP-PEST negatively regulate nephrin tyrosine phosphorylation. PTP1B directly binds to and dephosphorylates nephrin, while the action of PTP-PEST is indirect. The two phosphatases are also upregulated in the glomerulus in the rat model of puromycin aminonucleoside nephrosis. Both overexpression and inhibition of PTP1B deranged the actin cytoskeleton in cultured mouse podocytes. Thus, protein tyrosine phosphatases may affect podocyte function via regulating nephrin tyrosine phosphorylation.

scholarly journals Constitutive secretion of serum albumin requires reversible protein tyrosine phosphorylation events in trans-Golgi

2005 ◽  
Vol 289 (3) ◽  
pp. C748-C756 ◽  
Author(s):  
Rachel J. Webb ◽  
Jacob D. Judah ◽  
Lee-Chiang Lo ◽  
Geraint M. H. Thomas
Keyword(s):  
Serum Albumin ◽  
Tyrosine Phosphorylation ◽  
Tyrosine Kinases ◽  
Kinase Inhibitor ◽  
Tyrosine Phosphatase ◽  
Protein Tyrosine Phosphatases ◽  
Protein Tyrosine Phosphorylation ◽  
Albumin Secretion ◽  
Protein Tyrosine ◽  
Constitutive Secretion

Serum albumin secretion from rat hepatocytes proceeds via the constitutive pathway. Although much is known about the role of protein tyrosine phosphorylation in regulated secretion, nothing is known about its function in the constitutive process. Here we show that albumin secretion is inhibited by the tyrosine kinase inhibitor genistein but relatively insensitive to subtype-selective inhibitors or treatments. Secretion is also blocked in a physiologically identical manner by the tyrosine phosphatase inhibitors pervanadate and bisperoxo(1,10-phenanthroline)-oxovanadate. Inhibition of either the kinase(s) or phosphatase(s) leads to the accumulation of albumin between the trans-Golgi and the plasma membrane, whereas the immediate precursor proalbumin builds up in a proximal compartment. The trans-Golgi marker TGN38 is rapidly dispersed under conditions that inhibit tyrosine phosphatase action, whereas the distribution of the cis-Golgi marker GM130 is insensitive to genistein or pervanadate. By using a specifically reactive biotinylation probe, we detected protein tyrosine phosphatases in highly purified rat liver Golgi membranes. These membranes also contain both endogenous tyrosine kinases and their substrates, indicating that enzymes and substrates for reversible tyrosine phosphorylation are normal membrane-resident components of this trafficking compartment. In the absence of perturbation of actin filaments and microtubules, we conclude that reversible protein tyrosine phosphorylation in the trans-Golgi network is essential for albumin secretion and propose that the constitutive secretion of albumin is in fact a regulated process.

scholarly journals Protein tyrosine phosphatases in cell adhesion

2021 ◽  
Vol 478 (5) ◽  
pp. 1061-1083
Author(s):  
Katherine A. Young ◽  
Laura Biggins ◽  
Hayley J. Sharpe
Keyword(s):  
Cell Adhesion ◽  
Tyrosine Kinases ◽  
Protein Tyrosine Phosphatases ◽  
Tyrosine Phosphatases ◽  
Post Translational Modifications ◽  
Protein Tyrosine ◽  
Surrounding Matrix ◽  
Cell Adhesions ◽  
Multicellular Organisms ◽  
Extracellular Environment

Adhesive structures between cells and with the surrounding matrix are essential for the development of multicellular organisms. In addition to providing mechanical integrity, they are key signalling centres providing feedback on the extracellular environment to the cell interior, and vice versa. During development, mitosis and repair, cell adhesions must undergo extensive remodelling. Post-translational modifications of proteins within these complexes serve as switches for activity. Tyrosine phosphorylation is an important modification in cell adhesion that is dynamically regulated by the protein tyrosine phosphatases (PTPs) and protein tyrosine kinases. Several PTPs are implicated in the assembly and maintenance of cell adhesions, however, their signalling functions remain poorly defined. The PTPs can act by directly dephosphorylating adhesive complex components or function as scaffolds. In this review, we will focus on human PTPs and discuss their individual roles in major adhesion complexes, as well as Hippo signalling. We have collated PTP interactome and cell adhesome datasets, which reveal extensive connections between PTPs and cell adhesions that are relatively unexplored. Finally, we reflect on the dysregulation of PTPs and cell adhesions in disease.

scholarly journals Porphyromonas gingivalis Tyrosine Phosphatase Php1 Promotes Community Development and Pathogenicity

mBio ◽  
2019 ◽  
Vol 10 (5) ◽  
Author(s):  
Young-Jung Jung ◽  
Daniel P. Miller ◽  
John D. Perpich ◽  
Zackary R. Fitzsimonds ◽  
Daonan Shen ◽  
...  
Keyword(s):  
Community Development ◽  
Phosphatase Activity ◽  
Tyrosine Phosphorylation ◽  
Porphyromonas Gingivalis ◽  
Tyrosine Phosphatase ◽  
Protein Tyrosine Phosphorylation ◽  
Tyrosine Phosphatases ◽  
Content Type ◽  
Protein Tyrosine

ABSTRACT Protein-tyrosine phosphorylation in bacteria plays a significant role in multiple cellular functions, including those related to community development and virulence. Metal-dependent protein tyrosine phosphatases that belong to the polymerase and histindinol phosphatase (PHP) family are widespread in Gram-positive bacteria. Here, we show that Porphyromonas gingivalis, a Gram-negative periodontal pathogen, expresses a PHP protein, Php1, with divalent metal ion-dependent tyrosine phosphatase activity. Php1 tyrosine phosphatase activity was attenuated by mutation of conserved histidine residues that are important for the coordination of metal ions and by mutation of a conserved arginine residue, a key residue for catalysis in other bacterial PHPs. The php1 gene is located immediately downstream of the gene encoding the bacterial tyrosine (BY) kinase Ptk1, which was a substrate for Php1 in vitro. Php1 rapidly caused the conversion of Ptk1 to a state of low tyrosine phosphorylation in the absence of discernible intermediate phosphoforms. Active Php1 was required for P. gingivalis exopolysaccharide production and for community development with the antecedent oral biofilm constituent Streptococcus gordonii under nutrient-depleted conditions. In contrast, the absence of Php1 had no effect on the ability of P. gingivalis to form monospecies biofilms. In vitro, Php1 enzymatic activity was resistant to the effects of the streptococcal secreted metabolites pABA and H2O2, which inhibited Ltp1, an enzyme in the low-molecular-weight (LMW) phosphotyrosine phosphatase family. Ptk1 reciprocally phosphorylated Php1 on tyrosine residues 159 and 161, which independently impacted phosphatase activity. Loss of Php1 rendered P. gingivalis nonvirulent in an animal model of periodontal disease. Collectively, these results demonstrate that P. gingivalis possesses active PHP and LMW tyrosine phosphatases, a unique configuration in Gram-negatives which may allow P. gingivalis to maintain phosphorylation/dephosphorylation homeostasis in multispecies communities. Moreover, Php1 contributes to the pathogenic potential of the organism. IMPORTANCE Periodontal diseases are among the most common infections of humans and are also associated with systemic inflammatory conditions. Colonization and pathogenicity of P. gingivalis are regulated by signal transduction pathways based on protein tyrosine phosphorylation and dephosphorylation. Here, we identify and characterize a novel component of the tyrosine (de)phosphorylation axis: a polymerase and histindinol phosphatase (PHP) family enzyme. This tyrosine phosphatase, designated Php1, was required for P. gingivalis community development with other oral bacteria, and in the absence of Php1 activity P. gingivalis was unable to cause disease in a mouse model of periodontitis. This work provides significant insights into the protein tyrosine (de)phosphorylation network in P. gingivalis, its adaptation to heterotypic communities, and its contribution to colonization and virulence.

scholarly journals Regulation of Cell Adhesion by Protein-tyrosine Phosphatases

2006 ◽  
Vol 281 (23) ◽  
pp. 15593-15596 ◽  
Author(s):  
Keith Burridge ◽  
Sarita K. Sastry ◽  
Jennifer L. Sallee
Keyword(s):  
Cell Adhesion ◽  
Protein Tyrosine Phosphatases ◽  
Tyrosine Phosphatases ◽  
Protein Tyrosine
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