• KSBB Journal
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• v.24 no.3
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• pp.217-226
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• 2009

p53 undergoes various post-translational modifications, including phosphorylation, ubiquitination, sumoylation, acetylation, methylation, and poly(ADP-ribosyl)ation. Modification of p53 widely affects to various functions of p53. Acetylation and phosphorylation of p53 have been studied for regulating its transcriptional activity which is observed in various stress condition. Otherwise, ubiquitination of p53 by Mdm2 has been well-studied as a canonical ubiquitin-mediated proteasomal degradation pathway. Moreover several investigators have recently reported that ubiquitination of p53 modulates not only its proteasome-dependent degradation by poly-ubiquitination but also its localization and transcriptional activity by mono-ubiquitination which usually does not serve the proteasome dependent degradation. Here we review recent studies on the cellular functions of p53 regulated by post-translational modifications, particularly focusing on mechanisms of ubiquitination.

• Journal of Life Science
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• v.25 no.1
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• pp.1-7
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• 2015

Cyclin D is a member of the cyclin protein family, which plays a critical role as a core member of the mammalian cell cycle machinery. D-type cyclins (D1, D2, and D3) bind to and activate the cyclin-dependent kinases 4 and 6, which can then phosphorylate the retinoblastoma tumor suppressor gene products. This phosphorylation in turn leads to release or derepression of E2F transcription factors that promote progression from the G1 to S phase of the cell cycle. Among the D-type cyclins, cyclin D3 encoded by the CCND3 gene is one of the least well studied. In the present study, we have investigated the biochemistry of the proteolytic mechanism that leads to loss of cyclin D3 protein. Treatment of human prostate carcinoma PC-3-M cells with lovastatin and actinomycin D resulted in a loss of cyclin D3 protein that was completely reversible by the peptide aldehyde calpain inhibitor, LLnL. Additionally, using inhibitors for various proteolytic systems, we show that degradation of cyclin D3 protein involves the $Ca^{2+}$-activated neutral protease calpain. Moreover, the half-life of cyclin D3 protein half-life increased by at least 10-fold in PC-3M cells in response to the calpain inhibitor. We have also demonstrated that the transient expression of the calpain inhibitor calpastatin increased cyclin D3 protein in serum-starved NIH 3T3 cells. These data suggested that the function of cyclin D3 is regulated by $Ca^{2+}$-dependent protease calpain.

• Clinical and Experimental Reproductive Medicine
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• v.30 no.4
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• pp.261-269
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• 2003

목 적:본 연구에서는 생쥐 난소 주기에 따른Dazla 유전자의 발현 조절 양상을 관찰하고자 하였다. 연구재료 및 방법: 생후 27일된 암컷 미성숙 생쥐 (total 33EA; each 3 EA)로 부터 Pregnant Mare Serum Globulin (PMSG) 투여전, PMSG 투여 3시간, 6시간, 12시간, 24시간, 48시간 후 난소 조직과 hCG 투여 3시간, 6시간, 12시간, 24시간, 48시간 후 난소 조직을 획득하였다. 암컷 성숙 생쥐 난소와 (n=3) 수컷 성숙 생쥐 (n=3)로부터 고환 조직을 획득하여 대조군으로 사용하였다. 각각의 획득된 조직에서 Dazla mRNA 의 발현 여부를 RT-PCR과 in situ hybridization (ISH) 방법으로 확인하였다. 호르몬 투여 시기에 따른 Dazla 유전자의 발현 강도를 ISH 방법으로 비교하여 정상 난소주기에서 PMSG와 PMSG+hCG 에 의한 Dazla 유전자의 발현 조절 양상을 관찰하였다. 결 과: 미성숙 생쥐, 성숙 생쥐 난소 내 난자 모두에서Dazla 유전자의 발현이 관찰되었다. 성숙 생쥐 고환 내 정자에서도 Dazla 유전자의 발현이 관찰되었다. 미성숙 및 성숙 생쥐의 난포에서는 난포의 성장에 따라 Dazla 유전자의 발현 강도가 강하게 관찰되었다. 미성숙 생쥐에 투여된 PMSG와 PMSG+hCG에 의한 유전자의 발현 강도는 난포의 크기가 같을 경우 호르몬 투여전과 비교하여 차이가 없었다. 결 론: Dazla 유전자는 난소내 난자에서 특이하게 발현되며, 난포의 크기에 따라 난자에서의 dazla유전자 발현의 강도도 증가한다. 그러나 PMSG와 PMSG+hCG에 의하여 유전자 발현이 조절되지 않은 것으로 보아 난소의 배란주기에 따른 유전자의 발현 양상에 변화가 없는 것으로 생각된다.

• Journal of Life Science
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• v.16 no.4
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• pp.598-604
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• 2006

The $Ca^{2+}-activated$ neutral protease calpain induced proteolysis has been suggested to play a role in certain cell growth regulatory proteins. Cyclin proteolysis is essential for cell cycle progression. D-type cyclins, which form an assembly with cyclin-dependent kinases (cdk4 and cdk6), are synthesized earlier in G1 of the cell cycle and seem to be induced in response to external signals that promote entry into the cell cycle. Here we show that cyclin D3 protein levels are regulated at the posttranscriptional level by calpain protease. Treatment of human breast carcinoma MDA-MB-231 cells with lovastatin and actinomycin D resulted in a loss of cyclin D3 protein that was completely reversible by the peptide aldehyde calpain inhibitor, LLnL. The specific inhibitor of the 26S proteasome, lactacystin, the lysosome inhibitors, ammonium chloride and chloroquine, and the serine protease inhibitor, phenylmethylsulfonylfluoride (PMSF), did not block the degradation of cyclin D3 by lovastatin and actinomycin D. Results of in vitro degradation of cyclin D3 by purified calpain showed that cyclin D3 protein is degraded in a $Ca^{2+}-dependent$ manner, and the half-life of cyclin D3 protein was dramatically increased in LLnL treated cells. These data suggested that cyclin D3 protein is regulated by the $Ca^{2+}-activated$ protease calpain.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.1
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• pp.187-192
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• 2017

In dense deployments of sensor nodes in Wireless Sensor Networks, the MAC protocol has challenges to solve problems such as reducing delivery delay and reducing energy consumption. To solve these problems lots of protocols are suggested. This paper proposed a sensor nodes' residual energy based wake-up control mechanism, in which each node decides whether it wakes up or stays in sleep mode to save energy consumption by reducing unnecessary idle listening. The main idea of the wake-up control mechanism is to save node's energy consumption. The proposed wake-up control mechanism is based on the RI-MAC protocol, which is one of the receiver-initiated MAC protocols. A receiver node in the proposed mechanism periodically wakes up and broadcasts a beacon signal based on the energy status of the node. A receiver node also adjusts wake-up period based on the traffics. Results have shown that the proposed MAC protocol outperformed RI-MAC protocol in the terms of energy consumption.

• The Journal of the Acoustical Society of Korea
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• v.36 no.3
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• pp.194-201
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• 2017

Silla Great Bell was made to reproduce King Seongdeok Divine Bell and it was restored to have the same structure and patterns. The most difficult problem was to reproduce the magnificent striking sound and dynamic hum tone with strong beat like in King Seongdeok Divine Bell. Especially, beating sound is attributed to the uncontrollable asymmetry occurring in the casting process, so it can not be predicted or controlled before casting. In this study, we introduce the method and process to make Silla Great Bell have a strong beat with a proper period. Position conditions of mode pairs and striking point for a strong beat were identified. Bell thickness was locally decreased to make proper period of beat. The process was performed according to the simulation result of an equivalent bell model. As a result, the original weak and long beat was made to a strong beat with a proper period.

• Korean Journal of Family Social Work
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• no.23
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• pp.43-70
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• 2008

This study investigated the relationship between social support and caregiving self-efficacy among 530 mothers of persons with intellectual disabilities in their childhood(age 3-12), adolescence(age 13-18), and adulthood(age 19-35), exploring the moderating effect of the life span affiliation of the children with disabilities. The analysis revealed that greater perception of social support predicted higher level of caregiving self-efficacy for all the mothers. However, the moderating effect was detected indicating that there were differences in the effects of social support on caregiving self-efficacy across groups. Although social support was found to have some positive effects on caregiving self-efficacy for each group of mothers of both adolescents and adults, no effects for a group of mothers of children. These findings suggested that greater emphasis be placed on the expanded provision of social support for families of persons with intellectual disabilities in their developmental stages following the childhood.

• The Journal of the Acoustical Society of Korea
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• v.40 no.3
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• pp.192-200
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• 2021

Korean bell is a macroscopically axi-symmetrical structure, but has a slight asymmetry due to complex patterns and casting irregularity. Small asymmetry separates one vibration mode into a mode pair with slight frequency difference. The mode pair interferes and creates a beat. The vivid beat with an appropriate period makes the bell sound magnificent and lively feeling. In this study, we propose a method to make the vivid beat using artificial dumshoi. This method creates the vivid beat by designing artificial dumshoi that overwhelms the bell asymmetry. To this end, the asymmetry of Korean bell is quantified by analyzing the beat period data of a number of Korean bells cast in modern times. Based on the measured beat period data, the magnitude of asymmetry is quantified using an equivalent bell model and artificial dumshoi is applied. The movement of mode pair by dumshoi is predicted through finite element analysis. Finally, a design example of the artificial dumshoi for clear beat is introduced.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.61-61
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• 2003

Aquaporins (AQPs)는 다양한 상피세포와 내피세포에 존재하며 다량의 물 수송을 촉진하는 막성단백질로 현재 11개의 AQP가 (AQP0-10) 발견되었으나, 아직 생리적, 기능적 분석은 불충분한 상태이다. 생쥐의 자궁내막은 발정주기 동안 호르몬의 자극에 따라 부풀어오르거나 수축하는 변화를 보이며 에스트로젠과 몇몇 혈관에 작용하는 매개체에 의해 자궁 혈관의 투수성이 증가한다는 보고는 있으나, 자궁액의 수송 메커니즘에 대해서는 뚜렷하게 밝혀진 바가 없다. 발정기의 생쥐 자궁은 자궁내막세포의 증식과 함께 수화되는 특징을 보이며 자궁내강으로 물이 수송되어 luminal fluid의 점성이 낮아지는 현상이 나타나는데, 이 때 AQP가 water channel로서 중요한 역할을 할 것으로 보고 본 실험에서는 면역조직화학법(immunohistochemistry)과 역전사중합효소연쇄반응(Reverse-transcriptase polymerase chain reaction)을 통해 발정기 자궁의 수화와 AQP 발현의 상관성에 대해 알아보고자 하였다. 면역조직화학법의 결과 발정주기의 다른 시기에 비해 발정기(estrus phase)에 자궁상피세포에 AQP4, 5, 8 protein이 다량 존재하는 것으로 밝혀졌고, 근육층(myometrium)에서의 발현은 발정주기 동안 차이가 없었다. Whole uterus로 RT-PCR을 수행한 결과 AQP4, 5, 8 mRNA는 luteal phase에 비해 follicular phase에 더 많이 발현하는 것으로 확인되었다. 또한 LCM(Laser Capture Microdissection) system을 이용하여 luminal epithelium과 stromal cell을 분리하여 RT-PCR을 수행한 결과 AQP4, 5, 8 mRNA는 stromal cell 보다는 luminal epithelium에 더 많이 발현하며, 이 역시 follicular phase에 발현량이 증가함을 확인하였다. 이러한 결과로 미루어 생쥐 자궁에서 AQP4, 5, 8은 발정주기 내막에 발현이 증가하며 이는 자궁내강 안으로 수분을 수송하는데 주요한 기작으로 사료되며 estrogen에 의한 조절 가능성을 암시한다.

• Korean Journal of Environmental Biology
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• v.18 no.3
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• pp.291-298
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• 2000

Vitellogenesis, an important reproductive process in oviparous animals, includes the processes of hormonally regulated synthesis of yolk precursor protein, vitellogenin (Vg), and their deposition in ovarian oocytes as a vitellin which is an important energy source as well as buoyancy regulator of the egg. Vg genes consist of a gene family that encompasses a large number of lipoproteins and produce different Mr. Vg proteins in liver. The expression of Vg is largely dependent on the estrogen, and both reproductive cycle and temperature also influence Vg synthesis. Synthetic estrogens or estrogenic pollutants was sufficient to induce Vg in both sexes of oviparous vertebrates. Therefore, the estrogenic induction of vitellogenesis in male has been used for biological marker in the screening of estrogenicity of certain endocrine disrupting compounds and the monitoring the world-wide contamination of estrogenic compounds in wild life. In the studies on the biological hazard and influence of endocrine disrupting chemicals using the Vg induction in oviparous males, it is important to consider the reproductive cycle, zoogeography and biodiversity of the wild life animals in Korea.