Ivanov Andrei I, Nusrat Asma, Parkos Charles A
Epithelial Pathobiology Research Unit, Department of Pathology and Laboratory Medicine, Emory University, Room 115, 615 Michael Street, Atlanta, GA 30322, USA.
Bioessays. 2005 Apr;27(4):356-65. doi: 10.1002/bies.20203.
Tight junctions (TJ) and adherens junctions (AJ) regulate cell-cell adhesion and barrier function of simple polarized epithelia. These junctions are positioned in the apical end of the lateral plasma membrane and form the so-called apical junctional complex (AJC). Although initially seen as purely structural features, the AJC is now known to play important roles in cell differentiation and proliferation. The AJC is a highly dynamic entity, undergoing rapid remodeling during normal epithelial morphogenesis and under pathologic conditions. There is growing evidence that remodeling of the AJC is mediated by internalization of junctional proteins. This review summarizes what is known about endocytic pathways, intracellular destinations and signaling cascades involved in internalization of AJC proteins. Potential biological roles for AJC endocytosis in maintaining functional apical junctions, reversible opening of epithelial barrier and disruption of intercellular adhesion are also discussed.
紧密连接（TJ）和黏着连接（AJ）调节单层极化上皮细胞的细胞间黏附及屏障功能。这些连接位于外侧质膜的顶端，形成所谓的顶端连接复合体（AJC）。尽管最初被视为纯粹的结构特征，但现在已知AJC在细胞分化和增殖中发挥重要作用。AJC是一个高度动态的实体，在正常上皮形态发生过程及病理条件下会经历快速重塑。越来越多的证据表明，AJC的重塑是由连接蛋白的内化介导的。本综述总结了关于AJC蛋白内化所涉及的内吞途径、细胞内定位及信号级联的已知信息。还讨论了AJC内吞作用在维持功能性顶端连接、上皮屏障的可逆开放及细胞间黏附破坏方面的潜在生物学作用。
