极化上皮细胞中转运蛋白的分选(英文)

Transport protein sorting in polarized epithelial cells

上皮组织细胞必须极化其表面区域以执行其转运生理功能。不同膜转运蛋白定位于细胞膜的不同区域,而细胞与细胞之间则须通过紧密连接复合体紧密连接成极化区域,并调节旁细胞途径的通透性。精密的机体要求上皮细胞具备一个筛选装置,用于将新合成的转运蛋白定位于合适的表面区域;转运蛋白本身也必须内含规定其功能位置的分选信号。目前上皮细胞蛋白分选和蛋白质之间相互作用已被逐渐阐明。上皮细胞通过细胞信号转导途径形成极化初始状态,将自己定位于特定位置,调节细胞与细胞之间、细胞与基质之间的相互作用。最近研究发现其信号转导通路的一个成员是一种AMP激活的蛋白激酶(AMP-stimulated protein kinase,AMPK),它也是细胞能量感受器。

In order to carry out their physiological functions, the cells of transporting epithelial tissues must be able to polarize their cell surface domains. Different collections of membrane transport proteins must be distributed to distinct domains of the plasma membrane, and cells must be coupled to one-another through junctional complexes that help organize polarized domains and regulate the permeability of the paracellular pathway. This exquisite organization requires that epithelial cells possess a sorting apparatus that can target newly synthesized transport proteins to the appropriate surface domains. Furthermore, the transport proteins themselves must possess information embedded within their structures that specifies their sites of ultimate functional residence. The nature of this information, and of the protein-protein interactions involved in its interpretation, is beginning to be elucidated. The initial formation of the polarized state involves signaling cascades that epithelial cells use to orient themselves to sites of cell-cell and cell-matrix contact. Recent evidence suggests that one component of these cascades is a kinase that also serves as a cellular energy sensor.