PROCESSING OF TRANSFORMING GROWTH-FACTOR-BETA-1 PRECURSOR BY HUMAN FURIN CONVERTASE
PROCESSING OF TRANSFORMING GROWTH-FACTOR-BETA-1 PRECURSOR BY HUMAN FURIN CONVERTASE
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DOI：
10.1074/jbc.270.18.10618
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发表时间：
1995-05-05
影响因子：
4.8
通讯作者：
LEDUC, R
中科院分区：
文献类型：
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作者：
DUBOIS, CM;LAPRISE, MH;LEDUC, R
转化生长因子β前体（pro-TGF β）的蛋白水解加工是形成生物活性TGF β同型二聚体蛋白（TGF β）的重要步骤。361个氨基酸的前体pro-TGF β 1在其一级结构中具有在许多组成型分泌的前体蛋白中发现的R-H-R-R加工信号，并且可能被内切蛋白酶的哺乳动物转化酶家族的成员识别。为了确定是否可以通过弗林蛋白酶转化酶在体外实现pro-TGF β 1的切割，将纯化的前体在存在截短/分泌形式的酶的情况下孵育。免疫印迹显示，55-kDa的pro-TGF β 1被转化为44和12.5 kDa的条带，分别对应于proregion和成熟单体。用弗林蛋白酶处理pro-TGF β 1导致生物活性TGF β 1的产生增加5倍。此外，当在弗林蛋白酶缺陷的LoVo细胞中表达时，没有观察到pro-TGF β 1的加工。相比之下，当pro-TGF β 1与弗林蛋白酶转化酶共表达时，观察到有效的加工。总的来说，这些结果提供了证据，证明在我们的实验系统中，TGF β 1前体被人弗林蛋白酶有效和正确地加工，从而允许释放生物活性肽。
Proteolytic processing of the transforming growth factor beta precursor (pro-TGF beta) is an essential step in the formation of the biologically active TGF beta homodimeric protein (TGF beta). The 361-amino-acid precursor pro-TGF beta 1 has within its primary structure the R-H-R-R processing signal found in many constitutively secreted precursor proteins and potentially recognized by members of the mammalian convertase family of endoproteases. To determine whether cleavage of pro-TGF beta 1 can be achieved by the furin convertase in vitro, purified precursor was incubated in the presence of a truncated/secreted form of the enzyme. Immunoblots showed that the 55-kDa pro-TGF beta 1 was converted into the 44 and 12.5 kDa bands corresponding to the proregion and the mature monomer, respectively. Treatment of pro-TGF beta 1 with furin resulted in a 5-fold increase in the production of biologically active TGF beta 1. Furthermore, when expressed in the furin-deficient LoVo cells, no processing of pro-TGF beta 1 was observed. In contrast, efficient processing was oberved when pro-TGF beta 1 was coexpressed with the furin convertase. Collectively, these results provide evidence that in our experimental systems the TGF beta 1 precursor is efficiently and correctly processed by human furin thus permitting release of the biologically active peptide.