• Journal of Life Science
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• v.27 no.3
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• pp.370-381
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• 2017

Protein dephosphorylation is important for cellular regulation, which is catalyzed by protein phosphatases. Among protein phosphatases, carboxy-terminal domain (CTD) phosphatases are recently emerging and new functional roles of them have been revealed. There are 7 CTD phosphatases in human genome, which are composed of CTD phosphatase 1 (CTDP1), CTD small phosphatase 1 (CTDSP1), CTD small phosphatase 2 (CTDSP2), CTD small phosphatase-like (CTDSPL), CTD small phosphatase-like 2 (CTDSPL2), CTD nuclear envelope phosphatase (CTDNEP1), and ubiquitin-like domain containing CTD phosphatase 1 (UBLCP1). CTDP1 dephosphorylates the second phosphor-serine of CTD of RNA polymerase II (RNAPII), while CTDSP1, STDSP2, and CTDSPL dephosphorylate the fifth phosphor-serine of CTD of RNAPII. In addition, CTDSP1 dephosphorylates new substrates such as mothers against decapentaplegic homologs (SMADs), cell division cycle-associated protein 3 (CDCA3), Twist1, tumor-suppressor protein promyelocytic leukemia (PML), and c-Myc. CTDP1 is related to RNA polymerase II complex recycling, mitosis regulation and cancer cell growth. CTDSP1, CTDSP2 and CTDSPL are related to transcription factor recruitment, tumor suppressor function and stem cell differentiation. CTDNEP1 dephosphorylates LIPIN1 and is related to neural tube formation and nuclear envelope formation. CTDSPL2 is related to hematopoietic stem cell differentiation. UBLCP1 dephosphorylates 26S proteasome and is related to nuclear proteasome regulation. In conclusion, noble roles of CTD phosphatases are emerging through recent researches and this review is intended to summarize emerging roles of CTD phosphatases.

• The Korean Journal of Pharmacology
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• v.29 no.1
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• pp.121-130
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• 1993

This study was done to classify the proteins involved in the specific phosphorylation using the rat peripheral blood lymphocytes (rPBL) stimulated with mitogens, phorbol 12-myristate 13-acetate (PMA) and concanavalin A (Con A). The lymphocytes were incubated with $^{32}P-orthophosphate$ before PMA or Con A stimulation. The migration patterns of the phosphorylated proteins of mitogen-treated rPBL in two dimensional electrophoretic fields were analyzed after autoradiography. The stimulation of the lymphocytes with PMA and Con A increased the phosphorylation of thirteen protein fractions. The phosphorylation intensities of the protein spots differ to the treatments of the cells with specific kinase inhibitors, H-7 and W-7. These protein fractions were grouped into 3 classes, namely, PKC-mediated, CaM kinase-mediated, and other kinase mediated proteins. The effect of the duration of the stimulation on the phosphorylated behaviors occurred concurrently, not sequentially, although each individual protein fraction had a different time for the peak phosphorylation during the stimulation period upto 30 minutes. The phosphoproteins found in the cytosolic soluble fraction were phosphorylated prior to those in the pellet, whose phosphorylations were sustained at a high level for over 10 minutes. The above results suggest that the early events in lymphocyte activation involve 3 different sets of proteins which are phosphorylated by CaM kinase, PKC and other kinases, and those kinases do not work sequentially, but rather, independently or cooperatively.

• Journal of Sericultural and Entomological Science
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• v.43 no.2
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• pp.116-124
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• 2001

To improve the functional properties as a food, silk fibroin was phosphorylated with STMP In the phosphorylation reaction of silk fibroin, the degree of phosphorylation was increased with high alkali index and treatment temperature. Depending on treatment time and concentration of STMP it was rapidly increased up to 1hr. and 50%, but slowly above that time and 100%. It was indicated in the results of FT-IR analysis and $\^$31/p NMR spectroscopy of phosphorylated fibroin that it had a close ∝-helix and poly-phosphate structure. The more phosphorylation of fibroin made more turbidity, foam expansion and foam stability, but less solubility. Emulsifying activity was increased up to P100, but slightly decreased above Pl00 and emulsifying stability was constantly increased on the progressing of phosphorylation.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.1
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• pp.127-128
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• 2003

본 연구는 퇴비화 과정 중 난용성 인산의 가용화와 무기태 인산의 변화를 알아보기 위하여 수행하였다. 비료와 퇴비중의 인산형태는 다른 성분들보다 토양에 흡착 또는 고정되거나 불용화 되는 양이 많아 작물의 흡수량이 적다. 시비된 인산의 흡수율은 낮고, 그 대부분은 난용화되기 때문에 토양에 축적되거나 세탈과 용탈에 의해 수질을 오염화시키는 주원인이 되고 있다. 퇴비화 과정중의 인산형태별 함량변화를 분석조사하여 작물에 시비되는 인산비료와 퇴비의 시용량을 적절하게 조절하여 인산의 과잉 시비량을 저감시키기 위한 연구이다. 돈분을 원료로 한 퇴비화 과정에서 단계별로 퇴비시료를 채취하여 총인산(T-P), 유효인산(Avail. -P)과 무기태인산분획별(Ca-P, Al-P, Fe-P)로 분석한 결과는 다음과 같다. 퇴적더미의 초기부피는 570L였으며, 약 2개월간의 퇴비화를 통해서 시료채취와 미생물등의 분해작용으로 최종부피는 430L정도로 감소하였다. 이는 초기의 부피보다 25% 감소하였다. 퇴적더미의 분해로 인한 용적밀도의 변화를 고려하면, 총인산 함량은 초기 약 17,500mg/kg에서 최종시료는 22,500mg/kg로 증가되었다. 또한 퇴비화가 진행됨에 따라 인산의 가용태가 증가하는 결과를 보였으며, 초기의 유효인산이 4,500mg/kg에서 최종시료에서는 8,900mg/kg으로 증가되었다. 그리고 무기태 인산분획별 인산의 형태별 변화를 조사한 결과, 퇴비화 과정 중 Ca-P의 경우 pH와의 중요한 상관관계를 갖고 있었다. 유기물분해를 통해 유리된 인산과 Ca은 난용태로 전환되는데, 초기의 약 10일 동안 Ca-P의 감소원인은 pH의 감소로 인한 Ca이 유리되는 정도가 낮기 때문인 것으로 해석된다. 초기 Ca-P형태의 인산함량은 11,900mg/kg으로 Fe-P와 Al-P보다 많았다. 또한 퇴비화가 안정화되어 부숙된 최종시료의 무기태 인산분획물 중 Ca-P는 18,000mg/kg로 증가하였으며, Ca-P>Al-P>Fe-P의 순 이었다. 그러나 Al-P와 Fe-P 형태의 무기태인산은 초기의 함량비율보다 다소 감소한 결과를 보였다. 결론적으로, 퇴비화과정 중 단계별 인산함량의 형태전환을 분석한 결과 총인산의 함량은 퇴비화가 안정화될수록 부피감소로 인한 인산함량이 증가하는 경향을 보였지만, 유기물질의 분해로 인한 원료내 인산의 형태가 불용태와 난용태에서 가용태 인산으로 전환되는 것을 도출하였다. 또한 무기태 인산분획물에서는 Ca-P 인산형태가 퇴비화가 진행될수록 증가한다는 결과를 얻었으며, Fe-P와 Al-P는 분해된 유기물의 킬레이트작용으로 감소되었다고 판단되며, 그 존재형태가 경쟁적임을 알 수 있었다. 따라서 화학비료와 퇴비의 시용이 병행될 경우에는 퇴비의 가용태 인산함량뿐만 아니라 무기태 인산의 함량을 분석한 후 인산질비료의 시비량을 조절해야할 것으로 판단된다.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.10a
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• pp.17-21
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• 1995

대부분의 인슐린의 작용들은 인슐린 수용체를 통하여 이루어진다. 인슐린이 수용체에 결합하면, 수용체 고유의 tyrosine kinase 효소활성의 증가를 유발시키며, 결과적으로 세포내에 존재하는 기질 단백질, IRS-1, 의 tyrosine 잔기의 인산화를 증가시키게 된다. 이후, 여러 형태의 serine / threonine protein kinase 의 연속적인 활성화가 일어난다. 이들에 부가해서, 인슐린의 효자는 세포핵 내에까지 전달되어 유전자 발현의 조절과 같은 세포핵 고유의 활동에도 관여한다. 현재, 세포막에서 시작된 인슐린의 신호들이 세포핵까지 전달되는 정확한 기전에 대해서는 알려진 바 없지만, 최근의 연구에 의하면 MAP Kinase 와 S6 Kinase 그리고 Transcription Factor AP-1의 중요성이 제시되고 있다. 특히 유전자 조절 기전에는 핵단백질인 transcription factor의 인산화 반응이 큰 역할을 한다고 보고되고 있는바, 본 연구에서 AP-1. transcription factor 의 인산화 반응이 인슐린의 신호전달계에 미치는 역할에 대하여 고찰하였다. 요약하면, AP-1 transcription factor의 구성원인 c-Jun, c-Fos 그리고 Fos 관련 단백질들의 인산화가 인슐린에 의해 증가되며, 동시에 그들의. DNA-binding activity 와 유전자 발현의 활성이 증가됨을 밝힘으로써, AP-1 transcription factor의 인산화 반응이 인슐린의 핵 내에서의 작용기전에 중요한 역할을 함이 제시되고 있다. 또한 AP-1 의 인산화 반응에 관여하는 세포핵 protein kinase로서 Casein Kinase II 의 중요성이 밝혀졌다.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.286-286
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• 1994

Thrombin (0.25 U/ml : TB), 소-피부 collagen (200 $\mu\textrm{g}$/ml : CG), adenosine 5'-diphesphate (4,0 $\times$ $10^{-5}$M : ADP), 및 epinephrine (4,0 $\times$ 10 $^{-5}$M : EPI)의 가토-혈소판 응집과 단백인산화작용에 미치는 PDE-I (3-isobutyl-1-methylxanthine : IBMX, 및 KR 30075), amitriptyline (AP), chlorpromazine (CP), 및 sodium nitrogrosside (SNP)의 염향을 비교-검토하였다. 그 결과, KR은 2,2 $\times$ $10^{-7}$M 이하의 $IC_{50}$/에서 EPI > ADP > CG > TB 순으로 각각을 억제하였으며, SNP 보다도 강하였고; KR-30075보다 약하나 IBMX, AP, 및 CP도 각 응집재의 작용을 억제하였으며 특히 EPI에 대하여 $10^{-8}$M 이하의 $IC_{50}$/에서 유의한 억제력을 보였다. 각 응집제들은 41 kD 인산화는 유의하게 증가시키며 47 kD와 20 kD 단백인산화는 감소시켰는데; 모든 항응집성 약물이 41 kD 인산화-증가는 유의하게 억제하였다, 아울러, AP와 CP는 47 kD 단백인산화-감소에 영향을 미치지 않았으나 20 kD 단백인산화-감소는 억제하였다. PDE-I (IBMX와 KR)와 SNP는 47 kD와 20 kD 단백인산화-감소를 다소 약화시켰으며, 43 kD와 22 kD 단백인산화를 KR > IBMX > SNP순으로 유의하게 증가시켰고, KR의 22 kD 단백인산화작용은 현저하였다.

• Journal of Life Science
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• v.17 no.2 s.82
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• pp.185-191
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• 2007

Akt/PKB plays pivotal roles in many physiological responses such as proliferation, differentiation, apoptosis, and angiogenesis. Here we show that tyrosine phosphorylation of Akt/PKB is essential for the subsequent phosphorylation at $Thr^{\308}$. Tyrosine phosphorylation of Akt/PKB was induced by stimulation of COS-7 cells with epidermal growth factor receptor (EGF) and its phosphorylation was significantly enhanced by constitutive targeting of Akt/PKB to the plasma membrane by myristoylation. Interestingly, incubation of affinity purified Myc-tagged Akt/PKB with purified EGF receptor resulted in tyrosine phosphorylation as well as $Ser^{\473}$ phosphorylation of Akt/PKB. In addition, tyrosine-phosphorylated Akt/PKB could directly associate with activated EGF receptor in vitro. Finally, alanine mutation at putative tyrosine phosphorylation site $(Tyr^{\326})$ abolished EGF induced $Thr^{\308}$ phosphorylation of wild type as well as constitutively active form of Akt/PKB. Given these results we suggest here that direct tyrosine phosphorylation of Akt/PKB by EGF receptor could be another mechanism of EGF-induced control of many physiological responses.

• Journal of Life Science
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• v.22 no.3
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• pp.428-436
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• 2012

Protein phosphorylation is a universal mechanism that regulates cellular activities. The brassinosteroid (BR) signal transduction pathway is a relay of phosphorylation and dephosphorylation cascades. It starts with the BR-induced activation of the membrane receptor kinase brassinosteroid insensitive 1 (BRI1), resulting in the dephosphorylation of transcription factors such as BZR1/BES2 and BZR2/BES1 followed by BR-induced gene expression. Brassinosteroid signal transduction research has progressed rapidly by identifying the phosphorylation/dephosphorylation site(s) of the BR-regulated kinase and phosphatase substrates with a simultaneous pursuit of mutant phenotypes. Autophosphorylation, transphosphorylation, and serine/threonine and tyrosine phosphorylation of the receptor protein kinases BRI1 and BRI1-associated kinase (BAK1) have increased the understanding of the regulatory role of those kinases during physiological and developmental processes in plants. The phosphorylation event initiated by BR is also found in the regulation of receptor-mediated endocytosis and the subsequent degradation of the receptor. However, the basic molecular links of the BR signal transduction pathway are not well understood regarding this phosphorylation/dephosphorylation event. This review summarizes the current state of BR signal transduction research to uncover the phosphorylation/dephosphorylation networks and suggests directions for future research on steroid signal transduction to gain a more comprehensive understanding of the process.

• Journal of Life Science
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• v.18 no.1
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• pp.114-119
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• 2008

The molecular machinery controlling cell cycle is centered around the regulation of the activity of maturation-promoting factor (MPF), a complex composed of a catalytic Cdc2 and the cyclinB regulatory subunit. Cdc2 kinase is inactivated by phosphorylation of inhibitory kinase, Wee1. It has been known that there are three different Wee1 kinases in the mammalian cell, Wee1A, Wee1B and Myt1. To investigate the regulatory mechanism of Wee1 kinases, the phosphorylation and degradation of Wee1A and Wee1B were checked in the Xenopus oocyte cell cycle. When Wee1 kinases were injected into frog oocyte, Wee1B was more stable than Wee1A. Wee1A and Wee1B kinase were phosphorylated by many kinases such as PKA and Akt. The roles of amino or carboxyl terminal in mouse Wee1A or Wee1B kinase were investigated using chimeric constructs. The degree of protein phosphorylation, degradation and cell cycle progression were different between chimeric constructs. The amino domain of Wee1A was implicated in the protein phosphorylation and degradation while amino domain of Wee1B and carboxyl domain of Wee1A were involved in the activity regulation. These results suggested that the domains of Wee1 kinase have different and significant roles in regulating the Wee1 kinases in the cell cycle progression.

• Journal of the Korean Wood Science and Technology
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• v.28 no.2
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• pp.75-79
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• 2000

To improve the adsorption of heavy metal ions in aqueous solutions. sawdust and bark of pine (Pinus densiflora) and oak(Quercus accutisima) were phosphorylated. The phosphorylated sawdust and bark contained phosphorous of 1.2~1.3% in the treatment for 1 hr and 1.4~1.7% for 2 hrs regardless of species and tree segments. The sawdust indicated considerable increase in the adsorption ratio of $Cu^{2+}$, $Zn^{2+}$ and $Cd^{2+}$, however the adsorption of $Pb^{2+}$ was a little increased. The pine sawdust was more effective in the adsorption of heavy metal ions than that of oak. While the bark indicated little adsorption efficiency of heavy metal ions.