Green K J, Jones J C
Department of Pathology, Northwestern University Medical School, Chicago, Illinois 60611, USA.
FASEB J. 1996 Jun;10(8):871-81. doi: 10.1096/fasebj.10.8.8666164.
Desmosomes and hemidesmosomes are the major cell surface attachment sites for intermediate filaments at cell-cell and cell-substrate contacts, respectively. The transmembrane molecules of the desmosome belong to the cadherin family of calcium-dependent adhesion molecules, whereas those in the hemidesmosome include the integrin class of cell matrix receptors. In each junction, the cytoplasmic domains of certain transmembrane junction components contain unusually long carboxy-terminal tails not found in those family members involved in linkage of actin to the cell surface. These domains are thought to be important for the regulation of junction assembly and specific attachment of intermediate filaments via associated adapter proteins. Recent developments have suggested the exciting possibility that these junctions, in addition to playing an important structural function in tissue integrity, are both acceptors and affectors of cell signaling pathways. Many desmosomal and hemidesmosomal constituents are phosphoproteins and in certain cases the function of specific phosphorylation sites in regulating protein-protein interactions is being uncovered. In addition, a more active role in transmitting signals that control morphogenesis during development and possibly even regulate cell growth and differentiation are being defined for cytoplasmic and membrane components of these junctions.
桥粒和半桥粒分别是细胞间和细胞与基质接触处中间丝的主要细胞表面附着位点。桥粒的跨膜分子属于钙依赖性黏附分子的钙黏蛋白家族，而半桥粒中的跨膜分子包括细胞基质受体的整合素类。在每个连接中，某些跨膜连接成分的胞质结构域含有异常长的羧基末端尾巴，这些尾巴在参与肌动蛋白与细胞表面连接的家族成员中未发现。这些结构域被认为对连接组装的调节以及通过相关衔接蛋白对中间丝的特异性附着很重要。最近的研究进展表明了一个令人兴奋的可能性，即这些连接除了在组织完整性中发挥重要的结构功能外，还是细胞信号通路的受体和影响因素。许多桥粒和半桥粒成分是磷蛋白，在某些情况下，调节蛋白质 - 蛋白质相互作用的特定磷酸化位点的功能正在被揭示。此外，这些连接的细胞质和膜成分在传递控制发育过程中形态发生甚至可能调节细胞生长和分化的信号方面正被确定发挥更积极的作用。
