The Role of Lipoprotein Processing by Signal Peptidase II in the Gram-positive Eubacterium Bacillus subtilis
The Role of Lipoprotein Processing by Signal Peptidase II in the Gram-positive Eubacterium Bacillus subtilis
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DOI：
10.1074/jbc.274.3.1698
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发表时间：
1999-01
期刊：
影响因子：
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通讯作者：
H. Tjalsma;V. Kontinen;Z. Prágai;Ho-Chen Wu;Rob Meima;G. Venemâ;S. Bron;M. Sarvas;J. V. van Dijl-J.-V.
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文献类型：
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作者：
H. Tjalsma;V. Kontinen;Z. Prágai;Ho-Chen Wu;Rob Meima;G. Venemâ;S. Bron;M. Sarvas;J. V. van Dijl-J.-V.
计算机辅助分析表明，枯草芽孢杆菌含有大约300个带有氨基末端信号肽的输出蛋白基因。其中约114种是脂蛋白，它们保留在细胞质膜上。我们利用缺乏Spase II的细胞，研究了信号肽酶II(Spase II)处理脂蛋白对细胞动态平衡的重要性。结果表明，在低温和高温条件下，脂蛋白处理对细胞活力是重要的，这表明在这些条件下，脂蛋白对生长是必不可少的。虽然某些脂蛋白是发育遗传力、孢子形成和萌发所必需的，但在没有Spase II的情况下，这些发育过程不受影响。缺乏Spase II的细胞积累了脂质修饰的前体和成熟形式的PRSA，PRSA是分泌蛋白质的折叠催化剂。这些形式的PRSA似乎活性降低，因为α-淀粉酶的分泌严重受损。出乎意料的是，在没有Spase II的情况下，处理分泌前蛋白的I型信号肽酶不参与前PRSA的替代氨基末端处理。总之，枯草杆菌中Spase II处理脂蛋白并不是脂蛋白功能所必需的，这一点令人惊讶，因为脂蛋白和II型SPase似乎在所有真细菌中都是保守的。
Computer-assisted analyses indicate thatBacillus subtilis contains approximately 300 genes for exported proteins with an amino-terminal signal peptide. About 114 of these are lipoproteins, which are retained in the cytoplasmic membrane. We have investigated the importance of lipoprotein processing by signal peptidase II (SPase II) for cellular homeostasis, using cells lacking SPase II. The results show that lipoprotein processing is important for cell viability at low and high temperatures, suggesting that lipoproteins are essential for growth under these conditions. Although certain lipoproteins are required for the development of genetic competence, sporulation, and germination, these developmental processes were not affected in the absence of SPase II. Cells lacking SPase II accumulated lipid-modified precursor and mature-like forms of PrsA, a folding catalyst for secreted proteins. These forms of PrsA seem to have a reduced activity, as the secretion of α-amylase was strongly impaired. Unexpectedly, type I signal peptidases, which process secretory preproteins, were not involved in alternative amino-terminal processing of pre-PrsA in the absence of SPase II. In conclusion, processing of lipoproteins by SPase II in B. subtilis is not strictly required for lipoprotein function, which is surprising as lipoproteins and type II SPases seem to be conserved in all eubacteria.