• 제목/요약/키워드: subunits

검색결과 760건 처리시간 0.02초

콩 종실 단백질의 유전변이 (Genetic variation of 7S and 11S globulins in soybean seed)

    • 한국자원식물학회지
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    • 제12권3호
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    • pp.198-203
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    • 1999
  • 콩 저장 단백질의 대부분은 globulin이며, 이중 7S와 11S가 70% 이상을 차지한다. 따라서 콩 단백질의 조성개량을 위해서는 11S/7S비율 조정이 우선되는데, 본 연구에서는 전기영동(SDS-PAGE)법을 사용하여 콩 단백질 7S와 11S를 분리 확인하고, 이들 분획 단백질의 유전변이를 분석하였다. 국내 3개지역에서 재배된 콩 장려품종 6계통들의 평균 7S 함량은 38.9% 이었고 11S는 61.2%의 함량을 나타내었다. 분산분석 결과 품종간에 는 유의성이 있었지만 지역간에는 변이가 없었으며, 품종 x 지역의 상호작용은 고도의 유의성을 나타내었다. 유전력은 7S분획중의 $\beta$함량이 72.7%로 높게 나타났다. 공분산을 이용한 상관계수 추정에서는 유전상관이 표현형 상관 보다 다소 높게 나타났다. 따라서 7S와 11S의 분획간 함량을 조정함으로써 콩 단백질의 조성을 개량할 수 있으리라 판단된다.

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Modulation of the Expression of the GABAA Receptor β1 and β3 Subunits by Pretreatment with Quercetin in the KA Model of Epilepsy in Mice -The Effect of Quercetin on GABAA Receptor Beta Subunits-

  • Moghbelinejad, Sahar;Rashvand, Zahra;Khodabandehloo, Fatemeh;Mohammadi, Ghazaleh;Nassiri-Asl, Marjan
    • 대한약침학회지
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    • 제19권2호
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    • pp.163-166
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    • 2016
  • Objectives: Quercetin is a flavonoid and an important dietary constituent of fruits and vegetables. In recent years, several pharmacological activities of quercetin, such as its neuroprotective activity and, more specifically, its anti-convulsant effects in animal models of epilepsy, have been reported. This study evaluated the role of quercetin pretreatment on gene expression of ${\gamma}$-amino butyric acid type A ($GABA_A$) receptor beta subunits in kainic acid (KA)-induced seizures in mice. Methods: The animals were divided into four groups: one saline group, one group in which seizures were induced by using KA (10 mg/kg) without quercetin pretreatment and two groups pretreated with quercetin (50 and 100 mg/kg) prior to seizures being induced by using KA. Next, the messenger ribonucleic acid (mRNA) levels of the $GABA_A$ receptor ${\beta}$ subunits in the hippocampus of each animal were assessed at 2 hours and 7 days after KA administration. Quantitative real-time polymerase chain reaction (RT-PCR) assay was used to detect mRNA content in hippocampal tissues. Results: Pretreatments with quercetin at doses of 50 and 100 mg/kg prevented significant increases in the mRNA levels of the ${\beta}_1$ and the ${\beta}_3$ subunits of the $GABA_A$ receptor at 2 hours after KA injection. Pretreatment with quercetin (100 mg/kg) significantly inhibited ${\beta}_1$ and ${\beta}_3$ gene expression in the hippocampus at 7 days after KA injection. But, this inhibitory effect of quercetin at 50 mg/kg on the mRNA levels of the ${\beta}_3$ subunit of the $GABA_A$ receptor was not observed at 7 days after KA administration. Conclusion: These results suggest that quercetin (100 mg/kg) modulates the expression of the $GABA_A$ receptor ${\beta}_1$ and ${\beta}_3$ subunits in the KA model of epilepsy, most likely to prevent compensatory responses. This may be related to the narrow therapeutic dose range for the anticonvulsant activities of quercetin.

Characterization of Vitellin from the Fireflies, Luciola unmunsana and L. lateralis

  • Kim, Seong-Ryul;Bae, Jin-Sik;Jin, Byung-Rae;Kim, Jong-Gill;Kim, Keun-Young;Lee, Sang-Mong;Sohn, Hung-Dae
    • International Journal of Industrial Entomology and Biomaterials
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    • 제1권2호
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    • pp.131-135
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    • 2000
  • The vitellin of the fireflies, Luciola unmunsana and L. lateralis was characterized. The vitellin of L. unmunfon is composed of two subunits, designated Vnl (195 kDa) and Vn2 (185 kDa) in SDS-polyacryamide gel electrophoresis. These two subunits of vitellin of L. unmunsana gradually decreased during embryogenesis. As expected, these protein bands were presented in female adult hemolymph and egg extracts, but not in male. The vitellin of L. lateralis is also composed of two subunits, designated Vnl (195 kDa) and Vn2 (180 kDa) in SDS-PAGEi and these two protein bands gradually decreased during embryogenesis. Western blot analysis using each of polyclonal antiserum against vitellins of L. unmunsana and L. lateralis showed that two antisera strongly crossereacted with vitellin subunits of L. unmunsana and L. lateralis, suggesting that vitellins of L. unmunsana and L. lateralis have similarity with each other.

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CHIP promotes the degradation of mutant SOD1 by reducing its interaction with VCP and S6/S6' subunits of 26S proteasome

  • Choi, Jin-Sun;Lee, Do-Hee
    • Animal cells and systems
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    • 제14권1호
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    • pp.1-10
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    • 2010
  • Previously we showed that CHIP, a co-chaperone of Hsp70 and E3 ubiquitin ligase, can promote the degradation of mutant SOD1 linked to familial amyotrophic lateral sclerosis (fALS) via a mechanism not involving SOD1 ubiquitylation. Here we present evidence that CHIP functions in the interaction of mutant SOD1 with 26S proteasomes. Bag-1, a coupling factor between molecular chaperones and the proteasomes, formed a complex with SOD1 in an hsp70-dependent manner but had no direct effect on the degradation of mutant SOD1. Instead, Bag-1 stimulated interaction between CHIP and the proteasome-associated protein VCP (p97), which do not associate normally. Over-expressed CHIP interfered with the association between mutant SOD1 and VCP. Conversely, the binding of CHIP to mutant SOD1 was inhibited by VCP, implying that the chaperone complex and proteolytic machinery are competing for the common substrates. Finally we observed that mutant SOD1 strongly associated with the 19S complex of proteasomes and CHIP over-expression specifically reduced the interaction between S6/S6' ATPase subunits and mutant SOD1. These results suggest that CHIP, together with ubiquitin-binding proteins such as Bag-1 and VCP, promotes the degradation of mutant SOD1 by facilitating its translocation from ATPase subunits of 19S complex to the 20S core particle.

The Expression and the Subcellular Localization of Regulatory Subunits of Class IA Phosphoinositide 3-Kinase in L6 Skeletal Muscle Cell

  • Woo Joo-Hong;Lim Jeong-Soon;Kim Hye-Sun
    • 대한의생명과학회지
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    • 제12권3호
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    • pp.201-208
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    • 2006
  • PI3-kinase activity through p85, the regulatory subunit of class IA PI3-kinase, is indispensable for the growth, differentiation, and survival of skeletal muscle cells, but little is known about the function of other regulatory subunits such as p55 and p50. We examined the subcellular localization and the expression of the regulatory subunits of class IA PI3-kinase in L6 myoblasts. Both p55 and p50 as well as p85 were expressed in L6 myoblasts. Whereas p85 was localized at both cytosolic and nuclear tractions, p55 and p50 were localized at only the nuclear traction. During the differentiation of L6 myoblasts, the protein concentrations of both p55 and p50 were decreased but that of p85 was not significantly changed. Menadione-induced oxidative stress induced the translocation of p85 from cytosol to nucleus and the increase of p55 expression. These results suggest that the regulatory subunits of class IA PI3-kinase play an important role in L6 myoblasts.

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cDNA Sequences for Asialoglycoprotein Receptor from Human Fetal Liver

  • Lee, Dong-Gun;Lee, Sung-Gu;Kim, Kil-Lyong;Hahm, Kyung-Soo
    • BMB Reports
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    • 제30권4호
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    • pp.299-301
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    • 1997
  • The asialoglycoprotein receptor (ASGPR) was the first described mammalian lectin that mediates the specific binding and internalization of galactose/N-acetylgalactosamine-terminating glycoproteins by hepatic parenchymal cells. H1 and H2 are known as essential subunits of the functional ASGPR. There were close similarities in ASGPR H2 subunits between cultured cell line HepG2 and normal human liver cells including identical sequences at both termini. It was therefore expected that there may be some similarities between the subunits from normal liver cells and fetal liver cells. The two subunits of human fetal liver ASGPR. designated FL-H1 and FL-H2. were cloned from cDNA library by peR and the sequences were compared with the known HI and H2 sequences of HepG2, and the H1 sequence of nornal human liver cells. The results showed that FL-H1 was identical to H1 of HepG2. Whereas FL-H2 contains a 15-bp miniexon, but missing 57-bp at the near upstream from the membrane-spanning domain compared to H2 of HepG2 and normal human liver cells indicating that FL-H2 resulted from a differential splicing compared to HepG2 and normal liver cells.

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Recombinant α and β Subunits of M.AquI Constitute an Active DNA Methyltransferase

  • Pinarbasi, Hatice;Pinarbasi, Ergun;Hornby, David
    • BMB Reports
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    • 제35권3호
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    • pp.348-351
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    • 2002
  • AquI DNA methyltransferase, M.AquI, catalyses the transfer of a methyl group from S-adenosyl-L-methionine to the C5 position of the outermost deoxycytidine base in the DNA sequence 5'CYCGRG3'. M.AquI is encoded by two overlapping ORFs (termed $\alpha$ and $\beta$) instead of the single ORF that is customary for Class II methyltransferase genes. The structural organization of the M.AquI protein sequence is quite similar to that of other bacterial C5-DNA methyltransferases. Ten conserved motifs are also present in the correct order, but only on two polypeptides. We separately subcloned the genes that encode the $\alpha$ and $\beta$ subunits of M.AquI into expression vectors. The overexpressed His-fusion $\alpha$ and $\beta$ subunits of the enzyme were purified to homogeneity in a single step by Nickel-chelate affinity chromatography. The purified recombinant proteins were assayed for biological activity by an in vitro DNA tritium transfer assay. The $\alpha$ and $\beta$ subunits of M.AquI alone have no DNA methyltransferase activity, but when both subunits are included in the assay, an active enzyme that catalyses the transfer of the methyl group from S-adenosyl-L-methionine to DNA is reconstituted. We also showed that the $\beta$ subunit alone contains all of the information that is required to generate recognition of specific DNA duplexes in the absence of the $\alpha$ subunit.

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
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    • 제18권2호
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    • pp.155-161
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    • 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.