T-SP1: a novel serine protease-like protein predominantly expressed in testis.

Here, we describe a novel member in the group of membrane-anchored chymotrypsin (S1)-like serine proteases, namely testis serine protease 1 (T-SP1), as it is principally expressed in testis tissue. The human T-SP1 gene encompasses 28.7 kb on the short arm of chromosome 8 and consists of seven exons. Rapid amplification of cDNA ends (RACE) experiments revealed that due to alternative splicing three different variants (T-SP1/1, -2, -3) are detectable in testis tissue displaying pronounced heterogeneity at their 3′-end. T-SP1/1 consists of an 18 amino acid signal peptide and of a 49 amino acid propeptide. The following domain with the catalytic triad of His(108), Asp(156), and Ser(250) shares sequence identities of 42% and 40% with the blood coagulation factor XI and plasma kallikrein, respectively. Only T-SP1/1 contains a hydrophobic part at the C-terminus, which provides the basis for cell membrane anchoring. Using a newly generated polyclonal anti-T-SP1 antibody, expression of the T-SP1 protein was found in the Leydig and Sertoli cells of the testis and in the epithelial cells of the ductuli efferentes. Notably, T-SP1 protein was also detectable in prostate cancer and in some ovarian cancer tissues, indicating tumor-related synthesis of T-SP1 beyond testis tissue.

T-SP1:一种主要在睾丸中表达的新型丝氨酸蛋白酶样蛋白。

这里，我们描述了膜锚定胰凝乳蛋白酶(S1)样丝氨酸蛋白酶组中的一个新成员，即睾丸丝氨酸蛋白酶1 (T-SP1)，因为它主要在睾丸组织中表达。人类T-SP1基因包含8号染色体短臂上的28.7 kb，由7个外显子组成。cDNA末端快速扩增(RACE)实验表明，由于选择性剪接，在睾丸组织中可检测到三种不同的变体(T-SP1/1，-2，-3)，在其3’-末端显示出明显的异质性。T-SP1/1由18个氨基酸的信号肽和49个氨基酸的前肽组成。具有His(108)、Asp(156)和Ser(250)催化三联体的下列结构域分别与凝血因子XI和血浆激肽释放酶具有42%和40%的序列同一性。只有T-SP1/1在C末端含有疏水部分，这为细胞膜锚定提供了基础。使用新产生的多克隆抗T-SP1抗体，发现T-SP1蛋白在睾丸间质细胞和支持细胞以及输出小管上皮细胞中表达。值得注意的是，T-SP1蛋白在前列腺癌和一些卵巢癌组织中也可检测到，这表明T-SP1的肿瘤相关合成超出了睾丸组织。