Geis-Asteggiante Lucía, Dhabaria Avantika, Edwards Nathan, Ostrand-Rosenberg Suzanne, Fenselau Catherine
University of Maryland, College Park, MD. 20742. United States.
Georgetown University Medical Center, Washington, D.C. 20057. United States.
Int J Mass Spectrom. 2015 Feb 15;378:264-269. doi: 10.1016/j.ijms.2014.08.035.
Top-down analysis is reported for a portion of the protein cargo of exosomes shed by myeloid-derived suppressor cells that participate in intracellular signaling in the tumor microenvironment. Instrument mass resolution limited the study to proteins of molecular masses below 30 kDa. A two-step fractionation strategy was used, including open tubular gel electrophoresis and C3 reverse phase high performance liquid chromatography. Twenty-one unique proteins were identified among more than 200 proteoforms, and comprising primarily two functionally important protein families: the S100 proinflammatory mediators and an abundance of histones. Fifty-six percent of the total protein in these exosomes was determined to comprise histones, of which H2B variants contribute 42 %.
据报道，对髓源性抑制细胞释放的外泌体的部分蛋白质货物进行了自上而下的分析，这些外泌体参与肿瘤微环境中的细胞内信号传导。仪器质量分辨率将研究限制在分子量低于30 kDa的蛋白质上。采用了两步分级分离策略，包括开管凝胶电泳和C3反相高效液相色谱。在200多种蛋白质异构体中鉴定出21种独特的蛋白质，主要包括两个功能重要的蛋白质家族：S100促炎介质和大量组蛋白。这些外泌体中56%的总蛋白质被确定为组蛋白，其中H2B变体占42%。
