scholarly journals Regulated Endocrine-Specific Protein-18, an Emerging Endocrine Protein in Physiology: A Literature Review

Endocrinology ◽  
2019 ◽  
Vol 160 (9) ◽  
pp. 2093-2100
Author(s):  
Ealla Atari ◽  
Mitchel C Perry ◽  
Pedro A Jose ◽  
Sivarajan Kumarasamy
Keyword(s):  
Protein Tyrosine Phosphatase ◽  
Islet Cell ◽  
Tyrosine Phosphatase ◽  
Specific Protein ◽  
Targeted Disruption ◽  
Cervical Ganglion ◽  
Organ Specific ◽  
Intracellular Signal ◽  
Partial Homology ◽  
Reported Data

Abstract Regulated endocrine-specific protein-18 (RESP18), a novel 18-kDa protein, was first identified in neuroendocrine tissue. Subsequent studies showed that Resp18 is expressed in the adrenal medulla, brain, pancreas, pituitary, retina, stomach, superior cervical ganglion, testis, and thyroid and also circulates in the plasma. Resp18 has partial homology with the islet cell antigen 512, also known as protein tyrosine phosphatase, receptor type N (PTPRN), but does not have phosphatase activity. Resp18 might serve as an intracellular signal; however, its function is unclear. It is regulated by dopamine, glucocorticoids, and insulin. We recently reported that the targeted disruption of the Resp18 locus in Dahl salt-sensitive rats increased their blood pressure and caused renal injury. The aim of the present review was to provide a comprehensive summary of the reported data currently available, especially the expression and proposed organ-specific function of Resp18.

scholarly journals The STEP61 interactome reveals subunit-specific AMPA receptor binding and synaptic regulation

2019 ◽  
Vol 116 (16) ◽  
pp. 8028-8037 ◽  
Author(s):  
Sehoon Won ◽  
Salvatore Incontro ◽  
Yan Li ◽  
Roger A. Nicoll ◽  
Katherine W. Roche
Keyword(s):  
Ampa Receptors ◽  
Protein Tyrosine Phosphatase ◽  
Protein Phosphatase ◽  
Tyrosine Phosphatase ◽  
Hippocampal Slices ◽  
Specific Protein ◽  
Synaptic Proteins ◽  
Synaptic Currents ◽  
Synaptic Regulation ◽  
Binding Partners

Striatal-enriched protein tyrosine phosphatase (STEP) is a brain-specific protein phosphatase that regulates a variety of synaptic proteins, including NMDA receptors (NAMDRs). To better understand STEP’s effect on other receptors, we used mass spectrometry to identify the STEP61 interactome. We identified a number of known interactors, but also ones including the GluA2 subunit of AMPA receptors (AMPARs). We show that STEP61 binds to the C termini of GluA2 and GluA3 as well as endogenous AMPARs in hippocampus. The synaptic expression of GluA2 and GluA3 is increased in STEP-KO mouse brain, and STEP knockdown in hippocampal slices increases AMPAR-mediated synaptic currents. Interestingly, STEP61 overexpression reduces the synaptic expression and synaptic currents of both AMPARs and NMDARs. Furthermore, STEP61 regulation of synaptic AMPARs is mediated by lysosomal degradation. Thus, we report a comprehensive list of STEP61 binding partners, including AMPARs, and reveal a central role for STEP61 in differentially organizing synaptic AMPARs and NMDARs.

Setaria cervidual specific phosphatase: characterization and its effect on eosinophil degranulation

Parasitology ◽  
2009 ◽  
Vol 136 (8) ◽  
pp. 895-904 ◽  
Author(s):  
S. RATHAUR ◽  
R. RAI ◽  
E. SRIKANTH ◽  
S. SRIVASTAVA
Keyword(s):  
Protein Tyrosine Phosphatase ◽  
Tyrosine Phosphatase ◽  
Gel Filtration ◽  
Specific Protein ◽  
Enzyme Concentration ◽  
Cross Reactivity ◽  
Filarial Parasite ◽  
Significant Activity ◽  
Protein Tyrosine

SUMMARYSetaria cervi, a bovine filarial parasite contains significant acid phosphatase (AcP) activity in its various life stages. Two forms of AcP were separated from somatic extract of adult female parasite using cation exchange, gel filtration and concavalin affinity chromatography. One form having a molecular mass of 79 kDa was characterized as dual specific protein tyrosine phosphatase (ScDSP) based on substrate specificity and inhibition studies. With various substrates tested, it showed significant activity in the order of phospho-L-tyrosine>pNPP>ADP>phospho-L-serine. Inhibition by orthovanadate, fluoride, molybdate, and zinc ions further confirms protein tyrosine phosphatase nature of the enzyme. Km and Vmax determined with various substrates were found to be 16·66 mM, 25·0 μM/ml/min with pNPP; 20·0 mM, 40·0 μM/ml/min with phospho-L-tyrosine and 27·0 mM, 25·0 μM/ml/min with phospho-L-serine. KIwith pNPP and sodium orthovanadate (IC5033·0 μM) was calculated to be 50·0 mM. Inhibition with pHMB, silver nitrate, DEPC and EDAC suggested the presence of cysteine, histidine and carboxylate residues at its active site. Cross-reactivity withW. bancrofti-infected sera was demonstrated by Western blotting. ScDSP showed elevated levels of IgE in chronic filarial sera using ELISA. Underin vitroconditions, ScDSP resulted in increased effector function of human eosinophils when stimulated by IgG, which showed a further decrease with increasing enzyme concentration. Results presented here suggest thatS. cerviDSP should be further studied to determine its role in pathogenesis and the persistence of filarial parasite.

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