The cytoplasmic domain of CEACAM1-L controls its lateral localization and the organization of desmosomes in polarized epithelial cells
The cytoplasmic domain of CEACAM1-L controls its lateral localization and the organization of desmosomes in polarized epithelial cells
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DOI：
10.1242/jcs.00944
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发表时间：
2004-03-01
影响因子：
4
通讯作者：
Öbrink, B
中科院分区：
文献类型：
--
作者：
Sundberg, U;Beauchemin, N;Öbrink, B
具有不同胞质结构域的两种CEACAM1亚型CEACAM1-L和CEACAM1-S在极化的上皮MDCK细胞中不均匀分布。CEACAM1-S仅存在于顶端，而CEACAM1-L存在于顶端和侧部细胞表面。使用共聚焦显微镜和CEACAM1-L突变体，我们确定了几个氨基酸的细胞质结构域，是工具的横向定位。Tyr515，而不是Tyr488，构成了一个突出的横向靶向信号。过钒酸盐刺激的酪氨酸磷酸化诱导快速磷脂酰肌醇3-激酶依赖性消失的横向CEACAM1-L，而staurosporine，丝氨酸/苏氨酸激酶抑制剂，导致较慢的磷脂酰肌醇3-激酶独立的消失。两种药物均引起CEACAM1-L在晚期内体/溶酶体隔室中的积累。occludin、ZO-1、E-cadherin、beta-catenin和桥粒斑蛋白的共定位研究表明，侧向定位的CEACAM1-L存在于粘附连接中，但不存在于紧密连接或桥粒中。过表达CEACAM1-L不影响紧密连接或粘附连接蛋白的组织，但扰乱了桥粒的排列。细胞外表面桥粒数量明显减少，细胞角蛋白丝排列紊乱。桥粒扰动的信号位于胞质结构域C-末端部分的氨基酸484 - 518内，其中完整的Tyr515是必不可少的。
Two CEACAM1 isoforms with different cytoplasmic domains, CEACAM1-L and CEACAM1-S, are unequally distributed in polarized epithelial MDCK cells. CEACAM1-S is exclusively apical whereas CEACAM1-L occurs both in apical and lateral cell surfaces. Using confocal microscopy and CEACAM1-L mutants, we identified several amino acids in the cytoplasmic domain that were instrumental for the lateral localization. Tyr515, but not Tyr488, constituted a prominent lateral targeting signal. Pervanadate-stimulated Tyr phosphorylation induced rapid phosphatidylinositol 3-kinase-dependent disappearance of lateral CEACAM1-L, whereas staurosporine, a Ser/Thr kinase inhibitor, resulted in slower phosphatidylinositol 3-kinase-independent disappearance. Both drugs caused accumulation of CEACAM1-L in a late endosome/lysosome compartment. Colocalization studies of occludin, ZO-1, E-cadherin, beta-catenin and desmoplakin indicated that laterally localized CEACAM1-L was present in adherens junctions but not in tight junctions or desmosomes. Overexpressed CEACAM1-L did not affect the organization of tight junction or adherens junction proteins, but perturbed the arrangement of desmosomes. The abundance of desmosomes in the lateral cell surfaces decreased significantly and the submembraneous cytokeratin filaments became disorganized. The signal for desmosomal perturbance resided within amino acids 484-518 in the C-terminal part of the cytoplasmic domain, among which an intact Tyr515 was indispensable.