SYNTHESIS AND FUNCTION OF A TRANSFORMATION-DEPENDENT SECRETED LYSOSOMAL PROTEASE

恶性转化或治疗后培养的小鼠成纤维细胞 在TPA或PDGF等生长因子的作用下合成和分泌39,000 组织蛋白L的MR前体(也称为MEP，主要排泄蛋白) 数量很大。组织蛋白酶L是一种具有活性的酸性蛋白水解酶 是糖基化的。转化、TPA和PDGF刺激转录 我们从小鼠中克隆了一个具有功能的组织蛋白酶原L基因。 并对其5‘侧翼区进行了鉴定和测序 CAT构建中的启动子。受调控的转录需要序列 在前两个外显子和内含子中与上游启动子协同作用 元素。人L原蛋白基因也已被克隆和测序。一个 重组人血管紧张素原L的生物活性研究 细菌表明，细菌的“亲”部分和羧基末端部分都 蛋白质是充分活动所必需的。这篇“亲”的文章似乎是 参与酶的适当折叠，而羧基末端片段 半胱氨酸对运动也是必不可少的，大概是因为它能 与大的催化亚基形成二硫键。 抗人组织蛋白酶L的多克隆和单抗已研制成功 用重组人抗原制备。使用人类前组织蛋白酶 L基因探针，我们发现了L原蛋白在全人类中的表达。 组织和细胞系检测，肾癌组织和细胞系表达增加 和肺鳞状细胞癌。

Cultured mouse fibroblasts which are malignantly transformed or treated with TPA or growth factors such as PDGF synthesize and secrete the 39,000 Mr precursor to cathepsin L (also called MEP, for major excreted protein) in large amounts. Cathepsin L is an active acid protease whether or not it is glycosylated. Transformation, TPA and PDGF stimulate transcription of cathepsin L. we have cloned a functional procathepsin L gene from the mouse and have identified and sequenced the 5' flanking region which acts as a promoter in CAT constructions. Regulated transcription requires sequences in the first two exons and introns acting in concert with upstream promoter elements. A human procathepsin L cDNA has also been cloned and sequenced. A study of the activity of recombinant human procathepsin L produced in bacteria indicates that both the "pro" and the carboxy-terminal part of the protein are needed for full activity. The "pro" piece appears to be involved in proper folding of the enzyme, while a carboxyterminal segment cysteine is also essential for activity, presumably because it allows formation of a disulfide bridge with the large catalytic subunit. Polyclonal and monoclonal antibodies to human cathepsin L have been prepared using the recombinant human antigen. Using the human procathepsin L cDNA probe, we have shown expression of procathepsin L mRNA in all human tissues and cell lines tested, with increased expression in renal cancer and squamous cell carcinoma of the lung.