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C-terminal fragment signaling of membrane-anchored growth factor HB-EGF

膜锚定生长因子 HB-EGF 的 C 端片段信号传导

基本信息

批准号：
15390097
负责人：
HIGASHIYAMA Shigeki
金额：
$ 9.92万
依托单位：
Ehime University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15390097/
关键词：
HB-EGF Shedding Transcriptional repressor PLZF EGF family metalloprotease gene regulation shedding repressor

项目摘要

Heparin-binding EGF-like growth factor(HB-EGF) is initially synthesized as a type I transmembrane protein (proHB-EGF). The proHB-EGF is shed by specific metalloproteases, releasing the N-terminal fragment into the extracellular space as a soluble growth factor (HB-EGF) and the C-terminal fragment (HB-EGF-C) into the intracellular space, where it prevents transcriptional repression by the promyelocytic leukemia zinc finger protein (PLZF). The goal of the present study was to characterize regulation of proHB-EGF shedding and study its temporal variations in HB-EGF-C localization throughout the cell cycle. Quantitative combination analyses of cell surface proHB-EGF and HB-EGF in conditioned medium showed that proHB-EGF shedding occurred during the G1 cell cycle phase. Laser scanning cytometry revealed that HB-EGF-C was internalized into the cytoplasm during the late G1 phase and accumulated in the nucleus beginning in the S phase. Subsequent nuclear export of PLZF occurred during the late S phase. Further, HB-EGF-C was localized around the centrosome following breakdown of the nuclear envelope and was localized to the interzonal space with chromosome segregation in the late M phase. Temporal variations in HB-EGF localization throughout the cell cycle were also characterized by time-lapse imaging of cells expressing YFP-tagged proHB-EGF, and these results were consistent with those obtained in cytometry studies. Furthermore, we identified BCL-6 and BAZF as transcriptional repressors targeted by HB-EGF-C. These results indicate that proHB-EGF shedding and subsequent HB-EGF-C signaling are related with progression of the cell cycle and may provide a clue to understand the unique biological significance of non-receptor-mediated signaling of proHB-EGF in cell growth.

肝素结合表皮生长因子样生长因子(HB-EGF)最初是作为一种I型跨膜蛋白(proHB-EGF)合成的。ProHB-EGF是由特定的金属蛋白酶释放的，将N端片段释放到细胞外空间作为可溶性生长因子(HB-EGF)，将C端片段(HB-EGF-C)释放到细胞内空间，在那里它阻止早幼粒细胞白血病锌指蛋白(PLZF)的转录抑制。本研究的目的是表征ProHB-EGF脱落的调节，并研究其在整个细胞周期中HB-EGF-C定位的时间变化。条件培养液中细胞表面proHB-EGF和HB-EGF的定量组合分析表明，proHB-EGF脱落发生在细胞周期的G1期。激光扫描细胞术显示，HB-EGF-C在G1期晚期进入胞浆，S期开始在胞核蓄积。随后的PLZF核出口发生在S晚期。此外，HB-EGF-C在核膜破裂后定位于中心体周围，并定位于带间空间，染色体在M期晚期分离。表达YFP标记的proHB-EGF的细胞的时间推移成像也表征了HB-EGF在细胞周期中定位的时间变化，这些结果与细胞学研究中的结果一致。此外，我们还鉴定了BCL-6和BAZF是HB-EGF-C靶向的转录抑制因子。这些结果表明，proHB-EGF的脱落和随后的HB-EGF-C信号与细胞周期的进展有关，并可能为理解proHB-EGF的非受体介导的信号在细胞生长中的独特生物学意义提供线索。