• Title, Summary, Keyword: 2a protein

Search Result 17,478, Processing Time 0.084 seconds

A new purification method for the Fab and F(ab)2 fragment of 145-2C11, hamster anti-mouse CD3ε antibody

  • Kwack, Kyu-Bum
    • BMB Reports
    • /
    • v.33 no.2
    • /
    • pp.188-192
    • /
    • 2000
  • Recombinant protein G has been utilized in the purification of antibodies from various mammalian species based on the interaction of antibodies with protein G. The interaction between immunoglobulin and protein G may not be restricted to the Fc protion of antibodies, as many different $F(ab)_2$ or Fab fragments can also bind to protein G. I found both FAb $F(ab)_2$ of 145-2C11, a hamster anti-mouse $CD3{\varepsilon}$ antibody, bound to the protein G-sepharose. Interestingly, Fab and $F(ab)_2$ of 145-2C11 did not bind to the protein A-sepharose. The binding of Fab and $F(ab)_2$ of 145-2C11 to protein G provided a useful method to remove proteases, chopped fragments of the Fc region, and other contaminating proteins. The remaining intact antibody in the protease reaction mixture can be removed by using a protein A-sepharose, because the Fab and $F(ab)_2$ portions of 145-2C11 did not bind to protein A-sepharose. The specific binding of Fab and $F(ab)_2$ portions of 145-sC11 to a protein G-sepharose (though not to a protein A-sepharose) and binding of intact 145-2C11 to both protein A- and G-sepharose will be useful in developing an effective purification protocol for Fab and $F(ab)_2$ portions of 145-2C11.

  • PDF

Inhibitory Effect of Lipid Bilayer Membrane on Protein Phosphatase 2A (Protein Phosphatase 2A의 활성화에 미치는 Lipid Bilayer Membrane의 저해 효과)

  • 남기열
    • KSBB Journal
    • /
    • v.7 no.4
    • /
    • pp.302-307
    • /
    • 1992
  • Protein phosphatase 2A was obtained from a cytosolic fraction of bovine brain homogenate. The phosphatase activity using phosphorylated histone Hl as substrate was suppressed in the presence of liposomes composed of dipalmitoylphosphatidylcholine(DPPC) or the mixture of phosphatidylserine and DPPC. The binding of protein phosphatase to liposome was indicated by the facts that the phosphatase activity of the supernatant of protein phosphatase/multilayer vesicle mixture was decreased with increasing amount of liposome, and that [$^{125}I$]-labeled protein phosphatase was coeluted with liposome. However, the affinity of the protein for phospholipid membrane was not so high. On the other hand, okadaic acid and liposome reduced the phosphatase activity synergistically, which means that okadaic acid binds neither to lipid membrane nor to the membrane-associated phosphatase, The inhibitory effect of liposome was, therefore, ascribed to association of the protein phosphatase 2A with the lipid bilayer membrane.

  • PDF

Arabidopsis nucleoside diphosphate kinase-2 as a plant GTPase activating protein

  • Shen, Yu;Han, Yun-Jeong;Kim, Jeong-Il;Song, Pill-Soon
    • BMB Reports
    • /
    • v.41 no.9
    • /
    • pp.645-650
    • /
    • 2008
  • Nucleoside diphosphate kinase (NDPK) is involved in multiple signaling pathways in mammalian systems, including G-protein signaling. Arabidopsis NDPK2, like its mammalian counterparts, is multifunctional despite its initial discovery phytochrome-interacting protein. This similarity raises the possibility that NDPK2 may play a role in G-protein signaling in plants. In the present study, we explore the potential relationship between NDPK2 and the small G proteins, Pra2 and Pra3, as well as the heterotrimeric G protein, GPA1. We report a physical interaction between NDPK2 and these small G proteins, and demonstrate that NDPK2 can stimulate their GTPase activities. Our results suggest that NDPK2 acts as a GTPase-activating protein for small G proteins in plants. We propose that NDPK2 might be a missing link between the phytochrome-mediated light signaling and G protein-mediated signaling.

Regulatory B Subunits of Protein Phosphatase 2A Are Involved in Site-specific Regulation of Tau Protein Phosphorylation

  • Yu, Un Young;Yoo, Byong Chul;Ahn, Jung-Hyuck
    • The Korean Journal of Physiology and Pharmacology
    • /
    • v.18 no.2
    • /
    • pp.155-161
    • /
    • 2014
  • Overexpression of amyloid precursor protein with the Swedish mutation causes abnormal hyperphosphorylation of the microtubule-associated protein tau. Hyperphosphorylated isoforms of tau are major components of neurofibrillary tangles, which are histopathological hallmarks of Alzheimer's disease. Protein phosphatase 2A (PP2A), a major tau protein phosphatase, consists of a structural A subunit, catalytic C subunit, and a variety of regulatory B subunits. The B subunits have been reported to modulate function of the PP2A holoenzyme by regulating substrate binding, enzyme activity, and subcellular localization. In the current study, we characterized regulatory B subunit-specific regulation of tau protein phosphorylation. We showed that the PP2A B subunit PPP2R2A mediated dephosphorylation of tau protein at Ser-199, Ser-202/Thr-205, Thr-231, Ser-262, and Ser-422. Down-regulation of PPP2R5D expression decreased tau phosphorylation at Ser-202/Thr-205, Thr-231, and Ser-422, which indicates activation of the tau kinase glycogen synthase kinase 3 beta ($GSK3{\beta}$) by PP2A with PPP2R5D subunit. The level of activating phosphorylation of the $GSK3{\beta}$ kinase Akt at Thr-308 and Ser-473 were both increased by PPP2R5D knockdown. We also characterized B subunit-specific phosphorylation sites in tau using mass spectrometric analysis. Liquid chromatography-mass spectrometry revealed that the phosphorylation status of the tau protein may be affected by PP2A, depending on the specific B subunits. These studies further our understanding of the function of various B subunits in mediating site-specific regulation of tau protein phosphorylation.

Kinetic Study on Dephosphorylation of Myelin Basic Protein by Some Protein Phosphates

  • 황인성;김진한;최명운
    • Bulletin of the Korean Chemical Society
    • /
    • v.18 no.4
    • /
    • pp.428-432
    • /
    • 1997
  • The dephosphorylation specificity of protein phosphatase 2A (PP2A), calcineurin (PP2B) and protein phosphatase 2C (PP2C) were studied in vitro using myelin basic protein (MBP) as a model substrate which was fully phosphorylated at multiple sites by protein kinase C (PKC) or cyclic AMP-dependent protein kinase (PKA). In order to determine the site specificity of phosphates in myelin basic protein, the protein was digested with trypsin and the radioactive phosphopeptide fragments were isolated by high performance liquid chromatography (HPLC) on reversed-phase column. Subsequent analysis and/or sequential manual Edman degradation of the purified phosphopeptides revealed that Thr-65 and Ser-115 were most extensively phophorylated by PKA and Ser-55 by PKC. For the dephosphorylation kinetics, the phosphorylated MBP was treated with calcineurin or PP2C with various time intervals and the reaction was terminated by direct tryptic digest. Both Thr-65 and Ser-115 residues were dephosphorylated more rapidly than any other ones by phosphatases. However it can be differentiated further by first-order kinetics that the PP2B dephosphorylated both Thr-65 and Ser-115 with almost same manner, whereas PP2C dephosphorylated somewhat preferentially the Ser-115.

  • PDF

Funcyional Studies on Gene 2.5 Protein of Bacteriophage T7 : Protein Interactions of Replicative Proteins (박테리오파아지 T7 의 기능에 관한 연구;복제단백질간의 단백질 상호작용)

  • 김학준;김영태
    • Journal of Life Science
    • /
    • v.6 no.3
    • /
    • pp.185-192
    • /
    • 1996
  • Bacteriophage T7 gene 2.5 protein, a single-stranded DNA binding protein, is required for T7 DNA replication, recombination, and repair. T7 gene 2.5 protein has two distinctive domains, DNA binding and C-terminal domain, directly involved in protein-protein interaction. Gene 2.5 protein participates in the DNA replication of Bacteriophage T7, which makes this protein essential for the T7 growth and DNA replication. What gene 2.5 protein makes important at T7 growth and DNA replication is its binding affinity to single-stranded DNA and the protein-protein important at T7 DNA replication proteins which are essential for the T7 DNA synthesis. We have constructed pGST2.5(WT) encoding the wild-type gene 2.5 protein and pGST2.5$\Delta $21C lacking C-terminal 21 amino acid residues. The purified GST-fusion proteins, GST2.5(WT) and GST2.5(WT)$\Delta$21C, were used for whether the carboxyl-terminal domain participates in the protein-protein interactions or not. GST2.5(WT) and GST2.5$\Delta$21C showed the difference in the protein-protein interaction. GST2.5(WT) interacted with T7 DNA polymerase and gene 4 protein, but GST2.5$\Delta$21C did not interact with either protein. Secondly, GST2.5(WT) interacts with gene 4 proteins (helicase/primase) but not GST2.5$\Delta$21C. these results proved the involvement of the carboxyl-terminal domain of gene 2.5 protein in the protein-protein interaction. We clearly conclude that carboxy-terminal domain of gene 2.5 protein is firmly involved in protein-protein interactions in T7 replication proteins.

  • PDF

A STUDY OF APIN-PROTEIN INTERACTIONS USING PROTEIN MICROARRAY (Protein microarray를 이용한 APin-단백질의 상호작용에 관한 연구)

  • Park, Joo-Cheol;Park, Sun-Hwa;Kim, Heung-Joong;Park, Jong-Tae;Youn, Seong-Ho;Kim, Ji-Woong;Lee, Tae-Yeon;Son, Ho-Hyun
    • Restorative Dentistry and Endodontics
    • /
    • v.32 no.5
    • /
    • pp.459-468
    • /
    • 2007
  • Protein microarray or protein chips is potentially powerful tools for analysis of protein-protein interactions. APin cDNA was previously identified and cloned from a rat odontoblast cDNA library. The purpose of this study was to investigate the APin-protein interactions during ameloblast differentiation. Protein microarray was carried with recombinant APin protein and MEF2, Aurora kinase A, BMPR-IB and EF-hand calcium binding protein were selected among 74 interacting proteins. Immortalized ameloblast cells (ALCs) were transfected with pCMV-APin construct and U6-APin siRNA construct. After transfection, the expression of the mRNAs for four proteins selected by protein micoarrays were assessed by RT-PCR. The results were as follows: 1. APin expression was increased and decreased markedly after its over-expression and inactivation, respectively. 2. Over-expression of the APin in the ALCs markedly down-regulated the expression of MEF2 and Aurora kinase A, whereas their expression remained unchanged by its inactivation. 3. Expression of BMPR-IB and EF-hand calcium binding protein were markedly increased by the over-expression of the APin in the ALCs, whereas expression of BMPR-IB remained unchanged and expression of EF-hand calcium binding protein was markedly decreased by its inactivation. These results suggest that APin plays an important role in ameloblast differentiation and mineralization by regulating the expression of MEF2, Aurora kinase A, BMPR-IB and EF-hand calcium binding protein.

Expression of Heat Shock Protein HspA2 in Human Tissues (인간 조직에서 Heat Shock Protein A2 (HspA2) 단백질의 발현)

  • Son, W.Y.;Hwang, S.H.;Han, C.T.;Lee, J.H.;Choi, Y.J.;Kim, S.;Kim, Y.C.
    • Clinical and Experimental Reproductive Medicine
    • /
    • v.26 no.2
    • /
    • pp.225-230
    • /
    • 1999
  • In mouse, the heat shock protein 70-2 (hsp70-2) is found to have special function in spermatogenesis. Based on the observation, the hypothesis that human hspA2 (human gene; 98.2% amino acid homology with hsp70-2) might have important function in spermatogenesis in human testes was proposed. To test the hypothesis, we examined the expression of hspA2 in human tissues. Expression vector pDMC4 for expression of the human hspA2 protein using pTricHisB (invitrogen, USA) was constructed and the expressed hspA2 protein was cross-reacted with antiserum 2A raised against mouse hsp70-2 protein. Based on the cross-reactivity, we determined the expression level of hspA2 protein in human tissues by western blot analysis using the antiserum 2A. We demonstrated that antiserum 2A antibodies detected human hspA2 protein with specificity which was produced in the E.coli expression system. On Western blot analyses, significant hspA2 expression was observed in testes with normal spermatogenesis, whereas a low level of hspA2 was expressed in testis with Sertoli-cell only syndrome. Also, a small amount of hspA2 was detected in breast, stomach, prostate, colon, liver, ovary, and epididymis. These results demonstrate that the hspA2 protein is highly expressed in male specific germ cells, which in turn suggests that hspA2 protein might playa specific role during meiosis in human testes as suggested in the murine model. However, further studies should be attempted to determine the function of hspA2 protein in human spermatogenesis.

  • PDF

Regulatory Action of Protein Tyrosine Kinase in Intracellular Calcium Mobilization in C5a-stimulated Neutrophils (C5a에 의해 자극된 호중구에서 세포내 칼슘동원에 대한 Protein Tyrosine Kinase의 조절작용)

  • Choi, Won-Tae;Han, Eun-Sook;Lee, Chung-Soo
    • The Korean Journal of Pharmacology
    • /
    • v.32 no.3
    • /
    • pp.417-424
    • /
    • 1996
  • The present study was done to examine the involvement of protein kinase C and protein tyrosine kinase in intracellular $Ca^{2+}$ mobilization in C5a-stimulated neutrophils. Although protein kinase C inhibitors, staurosporine and H-7 inhibited intracellular $Ca^{2+}$ release in C5a-stimulated neutrophils, they did not affect $Ca^{2+}$ influx across the plasma membrane and elevation of $[Ca^{2+}]_i$ C5a-induced intracellular $Ca^{2+}$ release and $Ca^{2+}$ influx were inhibited by protein tyrosine kinase inhibitors, genistein and methyl-2,5-dihydroxycinnamate. ADP-evoked elevation of $[Ca^{2+}]_i$ was inhibited by genistein and methyl-2,5-dihydroxycinnamate but was not affectd by staurosporine and H-7. Genistein and methyl-2,5-dihydroxycinnamate reduced the store-regulated $Ca^{2+}$ influx in thapsigargin-treated neutrophils, while the effect of staurosporine and H-7 was not detected. When neutrophils were preincubated wih phorbol 12-myristate 13-acetate, the stimulatory effect of C5a on the elevation of $[Ca^{2+}]_i$ was reduced. These results suggest that protein tyrosine kinase may be involved in control of intracellular $Ca^{2+}$ release and $Ca^{2+}$ influx across the plasma membrane in C5a-activated neutrophils.

  • PDF

Expression and Characterization of Uropathogenic Escherichia coli Adhesin Protein Linked to Cholera Toxin A2B Subunits in Escherichia coli TB1

  • Lee, Yong-Hwa;Ryu, Dong-Kyun;Kim, Byung-Oh;Pyo, Suhk-Neung
    • Journal of Microbiology and Biotechnology
    • /
    • v.13 no.4
    • /
    • pp.552-559
    • /
    • 2003
  • The FimH subunit of type 1-fimbriated Escherichiu coli (E. coli) has been determined as a major cause for urinary tract infections. Thus, to produce a possible vaccine antigen against urinary tract infections, the fimIH gene was genetically coupled to the ctxa2b gene and cloned into a pMAL-p2E expression vector. The chimeric construction of pMALfimH/ctxa2b was then transformed into E. coli K-12 TB1 and its nucleotide sequence was verified. A fusion protein, based on fusing adhesin to the cholera toxin subunit A2B (CTXA2B), was induced with 0.01 mM isopropyl-${\beta}-D-thiogalactoside$ (IPTG) for 4 h at $37^{\circ}C$ to yield a soluble fusion protein. The fusion protein was then purified by affinity chromatography. The expressed fusion protein was confirmed by SDS-PAGE and Western blotting using antibodies to the maltose binding protein (MBP) or the cholera toxin subunit B (CTXB), plus the N-terminal amino acid sequence was also analyzed. The orderly-assembled fusion protein was confirmed by a modified $G_{Ml}-ganglioside$ ELISA, using antibodies to adhesin. The results indicated that the purified fusion protein was an adhesin/CTXA2B protein containing E. coli adhesin and the $G_{Ml}-ganglioside$ binding activity of CTXB. Accordingly, this adhesin/CTXA2B protein may be a potential antigen for oral immunization against uropathogenic E. coli.