Autoproteolysis of the SEA module of rMuc3 C-terminal domain modulates its functional composition.
Autoproteolysis of the SEA module of rMuc3 C-terminal domain modulates its functional composition.
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DOI：
10.1016/j.abb.2010.08.013
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发表时间：
2010-11
影响因子：
3.9
通讯作者：
Zhi-hong Peng;Yonghong He;Yongtao Yang;Rong Zhu;Jian-ying Bai;Yicheng Li;Hao Yu;Xin Zhang;Lei Chen;Wensheng Chen;Dianchun Fang;Rong-quan Wang
中科院分区：
文献类型：
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作者：
Zhi-hong Peng;Yonghong He;Yongtao Yang;Rong Zhu;Jian-ying Bai;Yicheng Li;Hao Yu;Xin Zhang;Lei Chen;Wensheng Chen;Dianchun Fang;Rong-quan Wang
rMuc 3是一种典型的跨膜粘蛋白，在其C-末端结构域中含有一个174个氨基酸的结构域，称为SEA模块，该结构域在真核细胞中被切割。然而，rMuc 3 SEA模块被蛋白水解的机制及其生物学意义还有待阐明。在本研究中，我们发现rMuc 3 C-末端结构域在原核细胞中被切割在SEA组件内的LSKGSIVV基序处，在细菌中表达的纯化的携带突变的LSKASIVV基序的rMuc 3 C-末端结构域中发现切割的时间依赖性。因此，rMuc 3 SEA模块的切割依赖于自蛋白水解。rMuc 3 C-末端结构域SEA模块的自蛋白水解在具有rMuc 3 C-末端结构域的LoVo人结肠癌细胞的体外迁移和侵袭中起关键作用。在LoVo细胞中，rMuc 3 C-末端结构域诱导HER/ErbB 2磷酸化形式（py 1248）的显著活化。吉非替尼（ZD 1839）抑制磷酸化确实减弱了具有rMuc 3 C端结构域的LoVo细胞的迁移和侵袭。因此，rMuc 3 C-末端结构域在其SEA模块处经历自蛋白水解，其维持其对于由HER/ErbB 2磷酸化调节的信号传导过程的增强的可用性，以促进LoVo细胞的迁移和侵袭。
rMuc3 is a typical transmembrane mucin and contains a 174 amino acid domain called an SEA module in its C-terminal domain which is cleaved in eukaryotic cells. However, the mechanism by which the rMuc3 SEA module is proteolyzed and its biological significance has to be elucidated. In this study, we showed that the rMuc3 C-terminal domain was cleaved at LSKGSIVV motif within SEA module in prokaryotic cells, the time-dependence of the cleavage was found in the purified rMuc3 C-terminal domain carrying a mutated LSKASIVV motif expressed in bacteria. Thus, the cleavage of rMuc3 SEA module depended on autoproteolysis. The autoproteolysis of the SEA module of rMuc3 C-terminal domain played a critical role in the migration and invasion of the LoVo human colon cancer cells with rMuc3 C-terminal domain in vitro. The rMuc3 C-terminal domain induced a significant activation of HER/ErbB2 phosphorylated form (py1248) in LoVo cells. Inhibition of the phosphorylation by gefitinib (ZD1839) did attenuate migration and invasion of LoVo cells with rMuc3 C-terminal domain. Thus, rMuc3 C-terminal domain undergoes autoproteolysis at its SEA module, which maintains its availability for the potentiation of the signaling process that is modulated by HER/ErbB2 phosphorylation to promote the migration and invasion of LoVo cells.