Regulation of Myb3 Nuclear Translocation via Dynamic Association with a Protein Complex

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簡歷

基本資料

Project title

Code/計畫編號

NSC101-2320-B001-026

Translated Name/計畫中文名

經由蛋白質複合體之形成控制Myb3 之進核效率

Funding Organization/主管機關

National Science and Technology Council

Co-Investigator(s)/共同執行人

戴榮湘(計畫主持人)

Department/Unit

Institute of Biomedical Sciences (IBMS)

Website

https://www.grb.gov.tw/search/planDetail?id=2632599

Year

2012

Start date/計畫起

01-08-2012

Expected Completion/計畫迄

31-07-2013

Co-Investigator(s)

Pang-Hung Hsu

Bugetid/研究經費

1070千元

ResearchField/研究領域

生物技術(醫)；基礎醫學

陰道滴蟲感染是促進人類先天免疫不全病毒傳播之主要危險因子，而抗藥性蟲株之報告持續增加，顯示陰道滴蟲之感染可能危及公共衛生。宿主環境中鐵的含量主導了陰道滴蟲的致病因子表現，在先前的研究裏，我們探討鐵如何調控陰道滴蟲附著蛋白質 ap65-1 基因之轉錄活性，同時發現了三個參與在此一細胞活動的轉錄因子，Myb1、Myb2 及 Myb3。近來，我們發現 Myb2 進入細胞核由一個其有高度結構而埋藏於 DNA 鍵結區內的區域所主導；而Myb3 進入細胞核亦由一個類似的結構所主導。由於鐵的作用，Myb3 在細胞質中能形成一個由 6 個蛋白質組成將近 700-kDa 的複合體，其中包括了一個具有 Ankaryin repeat 的蛋白質 (ANK1)。當 Myb3 序列中之兩個酸性胺基酸群集區突變時，突變蛋白質無法如正常蛋白質般進入細胞核，且形成蛋白質複合體的比例大增，這兩個酸性胺基酸群集區前的 threonine 是可能的 casein kinase II 磷酸化位址，顯示 Myb3 離開蛋白質複合體需要casein kinase II 的作用。同時，過度表現 ANK1 於陰道滴蟲時，可導致核內 Myb2 及 Myb3 量的下降，顯示 ANK1 可能將 Myb2 及 Myb3 留在細胞質中。另方面Myb3 能與 CypA1 相作用，而 CypA1 之過度表現能促進 Myb3 進入細胞核，導致 AP65 附著蛋白質表現量增加。因 Ankaryin repeat 可做為蛋白質複合體形成時之骨架，探討 ANK1 在 Myb3 複合體形成上所扮演的角色，可進一步了解 Myb3 進入細胞核的控制機制。在本研究計劃中，我們希望能了解 Myb3 是如何離開蛋白質複合體而進入細胞核中，並去探討 Myb3 與 CypA1 或 ANK1 的作用機制。我們的研究將提供資訊，以進一步探討陰道滴蟲中不同 Myb 蛋白質進入細胞核的共同調控機制。 Iron is a key determinant in monitoring the expression of multiple virulence phenotypes in the human pathogen, Trichomonas vaginalis. As a major risk factor in the transmission of the human immunodeficiency virus and increasing reports on drug resistant clinical isolates, trichomoniasis caused by urogenital infection of the protozoan parasite poses an imminent threat to public health. Our previous studies on the mechanism underlying regulation of iron-inducible virulence expression have revealed the involvement of multiple Myb proteins, namely Myb1, Myb2 and Myb3, in transcription of an adhesion protein, ap65-1, gene. Recently, Myb2 was found to rely on a highly ordered structure embedded in R2R3 DNA-binding domain to mediate nuclear import. A similar domain, but with distinct structural features, was demonstrated to mediate nuclear translocation of Myb3. Myb3 may form a protein complex of ~700-kDa comprising ~6 proteins, including an ankaryin repeat-containing protein (ANK1), in the cytoplasm of cells in an iron-dependent manner. With mutations of either polyacidic clusters in helix 1 and helix 4 of the R2R3 domain, the mutant protein was restrained in the protein complex from entry into the nucleus. A threonine residue preceding each polyacidic sequence is a predicted site for the casein kinase II, implying a potential involvement of certain casein kinase in releasing Myb3 from the protein complex. Meanwhile, overexpression of ANK1 also resulted in a lower level of nuclear Myb2 and Myb3, implying that ANK1 may restrain Myb2 and Myb3 in the cytoplasm. Myb3 was found to interact with a cyclophilin, CyPA1, which may promote nuclear importation of Myb3, resulting in overall expression of the adhesion protein, AP65. Since ankaryin repeats may serve as scaffold for protein complex assembly, it is imperative to elucidate the role of ANK1 in the assembly of the protein complex. In this proposal, we aim to study how Myb3 is released from the protein complex prior to nuclear importation, and to characterize the interaction motifs between Myb3 and CyPA1 and between Myb3 and ANK1. This work is a continuation of our previous efforts on iron-inducible transcription regulation, and may shed light on to a common regulatory mechanism for nuclear importation of various Myb proteins of the protozoan parasite.

Keyword(s)

Trichomonas vaginalis
iron
transcription factor
Myb
nuclear importation
protein complex
陰道滴蟲
鐵
轉錄因子
Myb
入核機制
蛋白質複合體

DSpace CRIS

Regulation of Myb3 Nuclear Translocation via Dynamic Association with a Protein Complex

基本資料

Description