Katz Adriana, Waridel Patrice, Shevchenko Andrej, Pick Uri
Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel.
Mol Cell Proteomics. 2007 Sep;6(9):1459-72. doi: 10.1074/mcp.M700002-MCP200. Epub 2007 Jun 14.
The halotolerant alga Dunaliella salina is a recognized model photosynthetic organism for studying plant adaptation to high salinity. The adaptation mechanisms involve major changes in the proteome composition associated with energy metabolism and carbon and iron acquisition. To clarify the molecular basis for the remarkable resistance to high salt, we performed a comprehensive proteomics analysis of the plasma membrane. Plasma membrane proteins were recognized by tagging intact cells with a membrane-impermeable biotin derivative. Proteins were resolved by two-dimensional blue native/SDS-PAGE and identified by nano-LC-MS/MS. Of 55 identified proteins, about 60% were integral membrane or membrane-associated proteins. We identified novel surface coat proteins, lipid-metabolizing enzymes, a new family of membrane proteins of unknown function, ion transporters, small GTP-binding proteins, and heat shock proteins. The abundance of 20 protein spots increased and that of two protein spots decreased under high salt. The major salt-regulated proteins were implicated in protein and membrane structure stabilization and within signal transduction pathways. The migration profiles of native protein complexes on blue native gels revealed oligomerization or co-migration of major surface-exposed proteins, which may indicate mechanisms of stabilization at high salinity.
嗜盐藻类杜氏盐藻是研究植物对高盐度适应性的公认模式光合生物。其适应机制涉及蛋白质组组成的重大变化，这些变化与能量代谢以及碳和铁的获取相关。为阐明其对高盐具有显著抗性的分子基础，我们对质膜进行了全面的蛋白质组学分析。通过用一种不能透过膜的生物素衍生物标记完整细胞来识别质膜蛋白。蛋白质通过二维蓝色非变性/SDS-PAGE进行分离，并通过纳升液相色谱-串联质谱进行鉴定。在鉴定出的55种蛋白质中，约60%是整合膜蛋白或膜相关蛋白。我们鉴定出了新的表面包被蛋白、脂质代谢酶、一个功能未知的新膜蛋白家族、离子转运蛋白、小GTP结合蛋白和热休克蛋白。在高盐条件下，20个蛋白点的丰度增加，2个蛋白点的丰度降低。主要的盐调节蛋白与蛋白质和膜结构稳定以及信号转导途径有关。蓝色非变性凝胶上天然蛋白质复合物的迁移图谱显示主要表面暴露蛋白的寡聚化或共迁移，这可能表明了在高盐度下的稳定机制。
