The formation mechanisms of secretory granules and synaptic-like micro-vesicles by the lead of cholesterol in endocrine cells.

内分泌细胞中胆固醇引导的分泌颗粒和突触样微泡的形成机制。

• 批准号: 18500235
• 负责人: HOSAKA Masahiro
• 金额: $ 2.63万
• 依托单位: Gunma University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2006
• 资助国家: 日本
• 起止时间: 2006 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18500235/
• 关键词: neuroendocrine cells; secretory granule; synaptic-like micro-vesicle; lipid composition; cholesterol; sorting; secretogranin III; peptide hormones; 選別輸送; pHプローブ

The secretory granules (SGs) of neuroendocrine cells contain granin proteins in addition to peptide hormones and prohormone convertases. Granin-family proteins, including chromogranin A (CgA), chromogranin B, secretogranin II, secretogranin III (SgIII), and 7B2, are thought to condense peptide hormones to SGs. To investigate the sorting mechanisms of peptide hormones to the SGs, we selected CgA as a model protein. Then we addressed following four findings. 1) We have screened a rat brain cDNA library with a yeast two-hybrid system using CgA as a bait. Although membrane-bound proteins were initially expected, a soluble secretory protein, SgIII, was identified. Following analyses demonstrated that CgA requires the SgIII-binding domain for its targeting to the SGs, whereas SgIII does not need the CgA-binding domain to target to the SGs. 2) SgIII was localized to the secretory granule membrane (SGM) despite lacking the transmembrane region. SgIII directly binds to cholesterol components of the SGM and targets CgA to SGs. 3) SgIII and carboxypeptidase E (CPE; a different molecule of a sorting receptor for prohormones) core the separate functional sorting complex by anchoring to cholesterol-rich secretory granule membranes, and POMC-derived peptides are transferred from CPE to SgIII, and further to CgA. With this grant, I have studied the formation mechanisms of secretory granules and synaptic-like micro-vesicles by the lead of cholesterol in endocrine cells. Moreover, we have shown that SgIII can bind the aggregated form of CgA, suggesting that a small quantity of SgIII is enough to target a large quantity of CgA to the secretory granules.

神经内分泌细胞的分泌颗粒（SG）除了含有肽激素和激素原转化酶外，还含有颗粒蛋白。粒蛋白家族蛋白质，包括嗜铬粒蛋白A（CgA）、嗜铬粒蛋白B、分泌粒蛋白II、分泌粒蛋白III（SgIII）和7 B2，被认为将肽激素浓缩为SG。为了研究肽类激素对SGs的分选机制，我们选择CgA作为模型蛋白。然后我们讨论了以下四个发现。1)我们以CgA为诱饵，用酵母双杂交系统筛选了大鼠脑cDNA文库。虽然最初预期的膜结合蛋白，可溶性分泌蛋白，SgIII，被确定。以下分析表明，CgA需要SgIII结合结构域来靶向SG，而SgIII不需要CgA结合结构域来靶向SG。2)SgIII定位于分泌颗粒膜（SGM），尽管缺乏跨膜区。SgIII直接结合SGM的胆固醇组分，并将CgA靶向SGs。3)SgIII和羧肽酶E（CPE;激素原的分选受体的不同分子）通过锚定到富含胆固醇的分泌颗粒膜上来形成单独的功能分选复合物，并且POMC衍生的肽从CPE转移到SgIII，并进一步转移到CgA。利用该基金，我研究了胆固醇诱导内分泌细胞分泌颗粒和突触样微泡的形成机制。此外，我们已经表明，SgIII可以结合聚集形式的CgA，这表明少量的SgIII就足以将大量的CgA靶向分泌颗粒。

项目成果

ホルモンが分泌穎粒へ選別されるメカニズム

激素分类为分泌颗粒的机制

• 发表时间: 2007
• 期刊: 生化学(社団法人生化学) 79
• 作者: Takayanagi;S.;Hiroyama;T.;Yamazaki;S.;Nakajima;T.;Morita;Y.;Usui;J.;Eto;K.;Motohashi;T.;Shiomi;K.;Keino-Masu;K.;Masu;M.;Oike;Y.;Mori;S.;Yoshida;N.;Iwama;A.and Nakauchi;H;穂坂正博
• 通讯作者: 穂坂正博

Molecular probes for sensing the cholesterol composition of subcellular organelle membranes.

• DOI: 10.1016/j.bbalip.2006.06.016
• 发表时间: 2006-10
• 期刊: Biochimica et biophysica acta
• 作者: Rong Wang;M. Hosaka;Lu Han;Hiromi Yokota-Hashimoto;M. Suda;D. Mitsushima;S. Torii;T. Takeuchi

Effects of a depot formulation of the GnRH agonist leuprorelin on the ultrastrucure of male rat pitultray gonadotropes

GnRH 激动剂亮丙瑞林长效制剂对雄性大鼠垂体促性腺激素超微结构的影响

• 发表时间: 2008
• 期刊: Arch Histol Cytol 70
• 作者: Kitahara;K. Sakai;Y.;Hosaka;M. Hira;Y.;Kakizaki;H.;Watanabe;T.
• 通讯作者: T.

「抗DNP抗体を用いたコレステロール結合体」

“使用抗 DNP 抗体的胆固醇缀合物”

• 发表时间: 2007

A subset of p23 localized on secretory granules in pancreatic beta-cells.

• 发表时间: 2007
• 期刊: The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society
• 作者: M. Hosaka;Tsuyoshi Watanabe;Y. Yamauchi;Y. Sakai;M. Suda;Shin Mizutani;T. Takeuchi;T. Isobe