图示：细胞连接
细胞间存在多种形式的细胞连接。
紧密连接位于靠近细胞表面的顶端部分，作为O形环形成密封无泄漏的环境，严格控制液体、离子和小分子的移动。主要的紧密连接蛋白包括封闭蛋白（occludin）、封闭连接蛋白（claudin）以及封闭小带蛋白（zonula occludens，ZO）。肌动蛋白丝延伸至细胞质内。
粘着连接是类似于嵌缝的细胞附着，主要蛋白包括细胞膜间的连环蛋白和膜间的E钙粘着糖蛋白。肌动蛋白丝延伸至细胞质内。
桥粒是类似于铆钉的细胞附着。
由连接子蛋白组成的连接子提供了细胞间液体、离子和分子的转运通道。
Cells are connected by various components that form junctions.
The zonula occludens(闭锁小带又称紧密连接) toward the apical margin, acts as an "O" ring to provide a tight seal so there is no leakage, and movement of fluids, ions, and small molecules is rigorously controlled. Key proteins include occludin（封闭蛋白） and claudin（封闭连接蛋白） as well as several zonula occludens (ZO) proteins（封闭小带蛋白）. Actin（肌动蛋白） filaments extend out into the cytoplasm.
The zonula adherens（粘着连接） provides cellular attachment similar to caulking. Key proteins include catenins just inside the cell membranes and E-cadherin with calcium between the membranes. Actin filaments extend out into the cytoplasm.
The macula adherens, or desmosome（桥粒） provides cellular attachment similar to a rivet, with desmoglein（桥粒芯糖蛋白） and desmocollin（桥粒芯胶蛋白） proteins with calcium between the cell membranes linking two plaque regions with plakoglobin（盘状球蛋白） and desmoplakin（桥粒斑蛋白） proteins just inside the cell membrane. Intermediate filaments extend into the cytoplasm for anchoring.
The hemidesmosome(半桥粒) attaches the cell to the basement membrane.
Connexons(连接子) with connexin protein（连接子蛋白） provide conduits for fluid, ions, and molecules passing between cells.