癌胚抗原相关粘附分子1（CEACAM1）是近期发现的血小板内负性调节胶原受体GPⅥ的重要调控因子,CEACAM1-L胞内段的ITIMs可以抑制GPⅥ-FcRγ链复合物的ITAMs信号转导,但迄今对CEACAM1胞外段结构域在血小板功能调控中的作用仍知之甚少。前期研究提示：CEACAM1-IgC2结构域源性多肽可以抑制胶原引起的血小板活化，但其作用机制还有待进一步探讨。为此，我们提出：CEACAM1-IgC2结构域源性多肽可能通过负性调节GPⅥ的功能抑制血小板活化。我们将通过免疫荧光、流式细胞术、免疫印迹、免疫共沉淀等方法探讨CEACAM1-IgC2结构域源性多肽抑制胶原引起的血小板活化与机制，为阐明CEACAM1负性调节血小板活化的机制、研发新型抗血小板药物提供新的思路。

Recent studies indicated that CEACAM1 acts as an important negative regulator of collagen receptor GPⅥ. CEACAM1-L protein has two ITIMs that can inhibit ITAMs signaling pathway of GPⅥ-FcRγ chain complex. Until now, little is known about the role of the extracellular domain of CEACAM1 in regulating platelet function. Our previous results demonstrated that two polypeptides, which are from the IgC2 domains of human CEACAM1, might serve to negatively regulate GPⅥ mediated platelet responses. However, the role and underlying mechanism of the polypeptides in modulating collagen-platelets interaction remains unexplored. Therefore, this project intends to use immunofluorescence, flow cytometry, western blot and chromatin immunoprecipitation to explore the mechanisms of CEACAM1-IgC2 polyeptides negatively regulate collagen induced platelet activation. This may provide new theoretical basis to decipher other mechanisms of CEACAM1’s role in platelet function and to develop new antiplatelet reagents.