N-terminal cleavage and release of the ectodomain of Flt1 is mediated via ADAM10 and ADAM 17 and regulated by VEGFR2 and the Flt1 intracellular domain.
N-terminal cleavage and release of the ectodomain of Flt1 is mediated via ADAM10 and ADAM 17 and regulated by VEGFR2 and the Flt1 intracellular domain.
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DOI：
10.1371/journal.pone.0112794
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发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
Thomas CP
中科院分区：
文献类型：
--
作者：
Raikwar NS;Liu KZ;Thomas CP
Flt是细胞表面VEGF受体之一，其可以被切割以释放N-末端细胞外片段，其像交替转录的可溶性Flt 1（sFlt 1）一样可以拮抗VEGF的作用。在表达Flt 1的HUVEC和HEK 293细胞中，金属蛋白酶抑制剂减少Flt 1 N-末端切割。过表达的ADAM 10和ADAM 17增加切割，而敲低的ADAM 10和ADAM 17减少N-末端切割，表明这些金属蛋白酶负责Flt 1切割。蛋白激酶C（PKC）的激活增加了Flt 1的丰度和裂解，但这并不需要任何残基内的Flt 1的细胞内部分。蛋白酶体抑制剂ALLN增加Flt 1的丰度，这是PKC作用的叠加。去除Flt 1的整个胞质区域似乎刺激Flt 1的切割，并且Flt 1不再对ALLN敏感，这表明胞质区域含有降解结构域。在HEK 293细胞中敲低环指泛素连接酶c-CBL增加了Flt 1的表达，尽管它似乎不需要先前发表的Flt 1 C-末端的酪氨酸残基（1333 Y）。增加VEGFR 2表达增加VEGF刺激的sFlt 1表达，并逐渐减少Flt 1的切割，Flt 1保持与VEGFR 2作为异二聚体结合。我们的研究结果表明，分泌的sFlt 1和切割Flt 1将往往有局部效应作为VEGF拮抗剂时，从细胞表达VEGFR 2和更远的效果时，从细胞缺乏VEGFR 2释放。
Flt is one of the cell surface VEGF receptors which can be cleaved to release an N-terminal extracellular fragment which, like alternately transcribed soluble Flt1 (sFlt1), can antagonize the effects of VEGF. In HUVEC and in HEK293 cells where Flt1 was expressed, metalloprotease inhibitors reduced Flt1 N-terminal cleavage. Overexpression of ADAM10 and ADAM17 increased cleavage while knockdown of ADAM10 and ADAM17 reduced N-terminal cleavage suggesting that these metalloproteases were responsible for Flt1 cleavage. Protein kinase C (PKC) activation increased the abundance and the cleavage of Flt1 but this did not require any residues within the intracellular portion of Flt1. ALLN, a proteasomal inhibitor, increased the abundance of Flt1 which was additive to the effect of PKC. Removal of the entire cytosolic region of Flt1 appeared to stimulate cleavage of Flt1 and Flt1 was no longer sensitive to ALLN suggesting that the cytosolic region contained a degradation domain. Knock down of c-CBL, a ring finger ubiquitin ligase, in HEK293 cells increased the expression of Flt1 although it did not appear to require a previously published tyrosine residue (1333Y) in the C-terminus of Flt1. Increasing VEGFR2 expression increased VEGF-stimulated sFlt1 expression and progressively reduced the cleavage of Flt1 with Flt1 staying bound to VEGFR2 as a heterodimer. Our results imply that secreted sFlt1 and cleaved Flt1 will tend to have local effects as a VEGF antagonist when released from cells expressing VEGFR2 and more distant effects when released from cells lacking VEGFR2.
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影响因子：
4.8
作者：
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DOI：
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发表时间：
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影响因子：
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