Ebrahimnejad A, Flayeh R, Unteregger G, Wagener C, Brümmer J
Abteilung für Klinische Chemie, Klinik und Poliklinik für Innere Medizin, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, Hamburg, 20246, Germany.
Exp Cell Res. 2000 Nov 1;260(2):365-73. doi: 10.1006/excr.2000.5026.
CEACAM1 functions as an epithelial tumor suppressor and as an angiogenic growth factor. In the present study, utilizing differentially (serine/threonine or tyrosine) phosphorylated cytoplasmic domains of CEACAM1 and CEACAM3 as bait to isolate associated proteins from granulocyte extracts, we have identified human paxillin as a binding partner of the tyrosine-phosphorylated cytoplasmic CEACAM1 domain. CEACAM1-paxillin complexes were coimmunoprecipitated from extracts of granulocytes, the colonic cell line HT29, and HUVECs. We identified phosphorylated Tyr-488-a residue in the cytoplasmic CEACAM1 domain known to be essential for the tumor suppressive effect-to be necessary for this association. The CEACAM1-paxillin interaction was confirmed using laser scanning confocal microscopy analyses in granulocytes and HT29 cells, where CEACAM1 colocalizes with paxillin at the plasma membrane. In HUVECs a highly polarized expression pattern and colocalization of paxillin and CEACAM1 was observed. These findings support the findings that CEACAM1 is linked to the actin-based cytoskeleton.
癌胚抗原相关细胞黏附分子1（CEACAM1）作为一种上皮肿瘤抑制因子和血管生成生长因子发挥作用。在本研究中，利用CEACAM1和CEACAM3差异（丝氨酸/苏氨酸或酪氨酸）磷酸化的胞质结构域作为诱饵，从粒细胞提取物中分离相关蛋白，我们鉴定出人桩蛋白是酪氨酸磷酸化的胞质CEACAM1结构域的结合伴侣。CEACAM1 - 桩蛋白复合物从粒细胞、结肠癌细胞系HT29和人脐静脉内皮细胞（HUVECs）的提取物中共免疫沉淀出来。我们确定磷酸化的Tyr - 488（已知对肿瘤抑制作用至关重要的胞质CEACAM1结构域中的一个残基）对于这种结合是必需的。在粒细胞和HT29细胞中使用激光扫描共聚焦显微镜分析证实了CEACAM1 - 桩蛋白的相互作用，其中CEACAM1与桩蛋白在质膜处共定位。在HUVECs中观察到桩蛋白和CEACAM1高度极化的表达模式和共定位。这些发现支持了CEACAM1与基于肌动蛋白的细胞骨架相关的发现。
