• Title/Summary/Keyword: phosphatase inhibitor

Search Result 163, Processing Time 0.029 seconds

Inorganic Phosphate Has the Inhibitory Effect on Phosphotyrosyl Phosphatase Activity of Alkaline Phosphatase in Rabbit Plasma (인산에 의한 토끼 혈장 Alkaline Phosphatase의 Phosphotyrosyl Phosphatase 활성 저해)

  • Lee, Kyung Tae;Seo, Soong Hoon;Kim, Dong Hyun
    • Korean Journal of Clinical Pharmacy
    • /
    • v.9 no.1
    • /
    • pp.62-65
    • /
    • 1999

  • Inorganic phosphate (Pi) in rabbit plasma was found to block completely phosphotyrosine phosphatase (PTPase) activity without affecting the alkaline phosphatase (ALPase) activity. Our results provided that (1) PTPase activity and inhibitor are separated after G-25 gel-filtration. (2) This inhibitor is heat stable and trypsin-resistant and it can be removed by dialysis using 3 Kd cut-off tubing. (3) The elution pattern of the inhibitor is identical to that of Pi, and by performing a seperate run with inorganic phosphate. (4) The PTPase activity was recovered following an incubation with $CaCl_2$ (10 mM).

  • PDF

Inhibition of protein tyrosine phosphatase non-receptor type 2 by PTP inhibitor XIX: Its role as a multiphosphatase inhibitor

  • Le, Hien Thi Thu;Cho, Young-Chang;Cho, Sayeon
    • BMB Reports
    • /
    • v.50 no.6
    • /
    • pp.329-334
    • /
    • 2017

  • Protein tyrosine phosphatases (PTPs) play crucial roles in signal transduction and their functional alteration has been detected in many diseases. PTP inhibitors have been developed as therapeutic drugs for diseases that are related to the activity of PTPs. In this study, PTP inhibitor XIX, an inhibitor of CD45 and PTEN, was investigated whether it inhibits other PTPs. Protein tyrosine phosphatase non-receptor type 2 (PTPN2) was selectively inhibited by the inhibitor in a competitive manner. Drug affinity responsive target stability (DARTS) analysis showed that the inhibitor induces conformational changes in PTPN2. Phosphorylation levels of signal transducer and activator of transcription 3 (STAT3) at Tyr-705, a crucial site for STAT3 activation and target site of PTPN2, decreased upon exposure to the inhibitor. Our results suggest that PTP inhibitor XIX might be considered as an effective regulator of PTPN2 for treating diseases related to PTPN2.

  • https://doi.org/10.5483/BMBRep.2017.50.6.003 인용 PDF KSCI

Effects of Sodium Fluoride on the Water Transport in Leaves of Barley and Rice under Salt Stress in the Light

  • Hwang, Hong-Jin;Oh, Kwang-Hoon;Park, Phun-Bum;Lee, Choon-Hwan
    • Journal of Photoscience
    • /
    • v.11 no.1
    • /
    • pp.25-28
    • /
    • 2004

  • The kinetics of the loss of leaf fresh weight during incubation of barley and rice leaves in 9% or 15% NaCl solutions were biphasic, indicating the existence of a controlling mechanism for water transport. The first rapid phases reached their plateaus within 1 and 2 h in the case of rice and barley leaves, respectively. When barley leaves were fed with sodium fluoride, an inhibitor of phosphatase inhibitor, through their epicotyls for 3 h in darkness, prior to the treatment of NaCl, the biphasic pattern shown during NaCl treatment was disappeared resulting in linear decreases in the relative fresh weights. The results suggest that NaF accelerates salt-induced water efflux from plant cells, possibly by inhibiting the protection mechanism that may act in NaF-untreated leaves. The linear water loss can be explained in terms of phosphorylation of aquaporin by blocking its dephosphorylation in the presence of the phosphatase inhibitor to keep aquaporin in a phosphorylated form. However, the effect of NaF shown in barley leaves were not observed in rice. These results suggest that the regulation of water transport depends on plant species, and the mechanism for the controlling water transport in rice is different from that of barley.

  • PDF

Identification of Protein Phosphatase 4 Inhibitory Protein That Plays an Indispensable Role in DNA Damage Response

  • Park, Jaehong;Lee, Jihye;Lee, Dong-Hyun
    • Molecules and Cells
    • /
    • v.42 no.7
    • /
    • pp.546-556
    • /
    • 2019

  • Protein phosphatase 4 (PP4) is a crucial protein complex that plays an important role in DNA damage response (DDR), including DNA repair, cell cycle arrest and apoptosis. Despite the significance of PP4, the mechanism by which PP4 is regulated remains to be elucidated. Here, we identified a novel PP4 inhibitor, protein phosphatase 4 inhibitory protein (PP4IP) and elucidated its cellular functions. PP4IP-knockout cells were generated using the CRISPR/Cas9 system, and the phosphorylation status of PP4 substrates (H2AX, KAP1, and RPA2) was analyzed. Then we investigated that how PP4IP affects the cellular functions of PP4 by immunoprecipitation, immunofluorescence, and DNA double-strand break (DSB) repair assays. PP4IP interacts with PP4 complex, which is affected by DNA damage and cell cycle progression and decreases the dephosphorylational activity of PP4. Both overexpression and depletion of PP4IP impairs DSB repairs and sensitizes cells to genotoxic stress, suggesting timely inhibition of PP4 to be indispensable for cells in responding to DNA damage. Our results identify a novel inhibitor of PP4 that inhibits PP4-mediated cellular functions and establish the physiological importance of this regulation. In addition, PP4IP might be developed as potential therapeutic reagents for targeting tumors particularly with high level of PP4C expression.

  • https://doi.org/10.14348/molcells.2019.0014 인용 PDF KSCI HTML