Mitsui S, Yamada T, Okui A, Kominami K, Uemura H, Yamaguchi N
Department of Cell Biology, Research Institute for Neurological Diseases and Geriatrics, Kyoto Prefectural University of Medicine, Japan.
Biochem Biophys Res Commun. 2000 May 27;272(1):205-11. doi: 10.1006/bbrc.2000.2761.
cDNAs encoding two splicing variants of a serine protease, termed hippostasin, were isolated by a PCR-based cloning strategy. The difference of 5' nucleotide sequence resulted in the variation in the amino terminal ends of the two, brain and prostate, types of human hippostasin. The longest ORF of the brain-type was 250 amino acids with a putative signal peptide, while that of the prostate-type was 282 amino acids. Homology search using the amino acid sequence revealed that prostate-type hippostasin was identical to TLSP (PRSS20), which is expressed in human primary keratinocytes (1). Transient expression analysis showed that both brain- and prostate-type TLSP/hippostasin were secreted into the conditioned medium as about 40 kDa proteins. Human TLSP/hippostasin showed 47% and 45% identity to trypsinogen II and kallikrein, respectively. In fact, the recombinant human TLSP/hippostasin efficiently cleaved Bz-Phe-Arg-4-methylcoumaryl-7-amide, a kallikrein substrate, and weakly cleaved other substrates for kallikrein and trypsin. Northern blot analysis detected a 1.3 kb band in the whole brain and a 1.4 kb band in the prostate and the lung. In situ hybridization revealed that it was expressed preferentially by the pyramidal neurons in the human hippocampus and secretory epithelial cells in the prostate. These results indicated that TLSP/hippostasin is involved in the functions of the human central nervous system and prostate and that it is a multifunctional protease present in various organs.
通过基于聚合酶链反应（PCR）的克隆策略，分离出了编码一种丝氨酸蛋白酶两种剪接变体的互补DNA（cDNA），该丝氨酸蛋白酶被称为海马抑素。5'核苷酸序列的差异导致了人脑型和前列腺型这两种人海马抑素氨基末端的变异。脑型的最长开放阅读框（ORF）为250个氨基酸，带有一个假定的信号肽，而前列腺型的最长开放阅读框为282个氨基酸。使用氨基酸序列进行同源性搜索发现，前列腺型海马抑素与TLSP（PRSS20）相同，TLSP在人原代表皮细胞中表达（1）。瞬时表达分析表明，脑型和前列腺型TLSP/海马抑素均以约40 kDa的蛋白质形式分泌到条件培养基中。人TLSP/海马抑素与胰蛋白酶原II和激肽释放酶的同一性分别为47%和45%。事实上，重组人TLSP/海马抑素能有效切割激肽释放酶底物Bz-Phe-Arg-4-甲基香豆素-7-酰胺，并能微弱切割其他激肽释放酶和胰蛋白酶的底物。Northern印迹分析在全脑中检测到一条1.3 kb的条带，在前列腺和肺中检测到一条1.4 kb的条带。原位杂交显示，它在人海马中的锥体神经元和前列腺中的分泌上皮细胞中优先表达。这些结果表明，TLSP/海马抑素参与了人类中枢神经系统和前列腺的功能，并且它是一种存在于多种器官中的多功能蛋白酶。
