Length of the linking domain of human pro-tumor necrosis factor determines the cleavage processing.
Length of the linking domain of human pro-tumor necrosis factor determines the cleavage processing.
复制标题
人促肿瘤坏死因子连接结构域的长度决定了切割加工。
DOI：
10.1021/bi952183l
复制
发表时间：
1996
期刊：
影响因子：
2.9
通讯作者：
J. Klostergaard
中科院分区：
文献类型：
--
作者：
Ping Tang;Mien Chie Hung;J. Klostergaard
一些研究表明，只有一个切割位点(Ala-1/Val+1)参与了人前肿瘤坏死因子释放成熟肿瘤坏死因子的过程，而其他研究表明连接序列(残基-20到-1)可能是重要的。我们先前证明了一个前肿瘤坏死因子缺失突变体Delta-20-1能够形成一个三聚体结构，并以旁分泌的方式介导肿瘤坏死因子的细胞毒作用，而不会释放成熟的肿瘤坏死因子。我们在该区域构建了7个缺失较小的突变体。三个15个残基缺失突变体Delta-20-6、Delta-15-1和Delta-20-16、-10-1是不可切割的，但能够形成三聚体并通过细胞间接触介导细胞毒性。三个5个或10个残基缺失的突变体，Delta-20-16、Delta-10-1和Delta-5-，-1，表现出与野生型肿瘤坏死因子相似的行为；它们都形成了一个三聚体并释放了成熟的肿瘤坏死因子。这些结果表明，在前肿瘤坏死因子中，(1)三聚体碱基与质膜之间的残基数量决定了切割位点对前肿瘤坏死因子加工酶(S)的可及性，因为小的缺失不阻止切割，而大的缺失与天然切割位点(-1/+1)的存在无关；(2)天然切割位点不足以释放成熟的肿瘤坏死因子，因为天然切割位点完整的突变体Delta-20-6是不可切割的，(3)由于缺乏天然切割位点的突变体Delta-10-1和Delta-5-1是可切割的，因此可能存在选择性切割位点(S)。
Several studies have indicated that only one cleavage site (Ala-1/Val+1) is involved in the release of mature TNF from human pro-TNF, whereas others have suggested that the linking sequence (residues -20 to -1) may be important. We previously demonstrated that a pro-TNF deletion mutant, delta -20- -1, was able to form a trimeric structure and mediate TNF cytotoxicity in a juxtacrine fashion without releasing mature TNF. We constructed seven mutants with smaller deletions within this region. Three 15-residue deletion mutants, delta -20- -6, delta -15- -1 and delta -20- -16, -10- -1, were noncleavable, although able to form a trimer and to mediate cytotoxicity through cell-to-cell contact. Three five- or ten-residue deletion mutants, delta -20- -16, delta -10- -1, and delta -5-, -1, behaved like the wild-type TNF; all formed a trimer and released mature TNF. These results suggested that in pro-TNF (1) the number of residues between the base of the trimer and the plasma membrane determines accessibility of the cleavage site to the pro-TNF processing enzyme(s) since small deletions did not block cleavage whereas large ones did regardless of the presence of the native cleavage site (-1/+1), (2) the native cleavage site is not sufficient for releasing mature TNF because mutant delta -20- -6, in which the native cleavage site was intact, was noncleavable, and (3) alternative cleavage site(s) may exist since mutants delta -10- -1 and delta -5- -1, which lack the native cleavage site, were cleavable.