Global Topology Analysis of Pancreatic Zymogen Granule Membrane Proteins
Global Topology Analysis of Pancreatic Zymogen Granule Membrane Proteins
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DOI：
10.1074/mcp.m700575-mcp200
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发表时间：
2008-12-01
影响因子：
7
通讯作者：
Andrews, Philip C.
中科院分区：
文献类型：
--
作者：
Chen, Xuequn;Ulintz, Peter J.;Andrews, Philip C.
酶原颗粒是胰腺腺泡细胞中储存消化酶和调节分泌的特化细胞器，是研究分泌颗粒功能的经典模型。我们的长期目标是开发一个全面的结构模型酶原颗粒膜（ZGM）蛋白，将指导新的假设，为后续的功能研究。我们最初的蛋白质组学分析集中于鉴定来自纯化的ZGM的蛋白质（Chen，X.，步行者，A. K.，斯特拉勒，J.R.，西蒙，E.美国，Tomanicek-Volk，S. L.，纳尔逊，B。B.，Hurley，M. C.的方法，恩斯特，S。一、威廉姆斯，J. A.，和Andrews，P. C.（2006）细胞器蛋白质组学：胰腺酶原颗粒膜的分析。摩尔Cell. Proteomics 5，306 312）。在目前的研究中，一个新的全球拓扑结构分析ZGM蛋白的描述，适用于同位素富集方法的蛋白酶保护协议。我们的研究结果表明，ZGM蛋白的胰蛋白酶肽被分离成两个不同的集群，根据其同量异序标签的相对和绝对定量（iTRAQ）的比率为蛋白酶K处理与对照酶原颗粒。低iTRAQ比率簇包括细胞质定向膜和膜相关蛋白，包括肌球蛋白V、囊泡相关膜蛋白、突触融合蛋白和所有Rab蛋白。具有不变比率的第二簇主要包括管腔蛋白。因为定量是在肽水平，这种技术也能够映射从同一跨膜蛋白质的细胞质和管腔定向结构域。为了更准确地分配拓扑结构，我们开发了一种统计混合模型，以基于其iTRAQ比率提供所鉴定的肽为细胞质或管腔的概率。通过实施这种方法的ZGM蛋白的全局拓扑分析，我们在这里报告一个实验约束，全面的拓扑模型确定酶原颗粒膜蛋白。该模型有助于为开发ZGM的高阶结构模型和未来单个ZGM蛋白的功能研究奠定坚实的基础。Molecular & Cellular Proteomics 7：2323-2336，2008.
The zymogen granule is the specialized organelle in pancreatic acinar cells for digestive enzyme storage and regulated secretion and is a classic model for studying secretory granule function. Our long term goal is to develop a comprehensive architectural model for zymogen granule membrane (ZGM) proteins that would direct new hypotheses for subsequent functional studies. Our initial proteomics analysis focused on identification of proteins from purified ZGM (Chen, X., Walker, A. K., Strahler, J. R., Simon, E. S., Tomanicek-Volk, S. L., Nelson, B. B., Hurley, M. C., Ernst, S. A., Williams, J. A., and Andrews, P. C. (2006) Organellar proteomics: analysis of pancreatic zymogen granule membranes. Mol. Cell. Proteomics 5, 306 312). In the current study, a new global topology analysis of ZGM proteins is described that applies isotope enrichment methods to a protease protection protocol. Our results showed that tryptic peptides of ZGM proteins were separated into two distinct clusters according to their isobaric tag for relative and absolute quantification (iTRAQ) ratios for proteinase K-treated versus control zymogen granules. The low iTRAQ ratio cluster included cytoplasm-orientated membrane and membrane-associated proteins including myosin V, vesicle-associated membrane proteins, syntaxins, and all the Rab proteins. The second cluster having unchanged ratios included predominantly luminal proteins. Because quantification is at the peptide level, this technique is also capable of mapping both cytoplasm-and lumen-orientated domains from the same transmembrane protein. To more accurately assign the topology, we developed a statistical mixture model to provide probabilities for identified peptides to be cytoplasmic or luminal based on their iTRAQ ratios. By implementing this approach to global topology analysis of ZGM proteins, we report here an experimentally constrained, comprehensive topology model of identified zymogen granule membrane proteins. This model contributes to a firm foundation for developing a higher order architecture model of the ZGM and for future functional studies of individual ZGM proteins. Molecular & Cellular Proteomics 7: 2323-2336, 2008.