Fais Stefano, Malorni Walter
Laboratory of Immunology, Istituto Superiore di Sanità, Rome, Italy.
J Leukoc Biol. 2003 May;73(5):556-63. doi: 10.1189/jlb.1102568.
The acquisition of a cell polarity is a crucial requirement for migration, activation, and apoptosis of leukocytes. The polarization of leukocytes involves the formation of two distinct poles: the leading edge--the attachment cell site to the substrate allowing directional movements of the cell--and on the opposite side, the uropod--mostly involved in cell-to-cell interaction and in a variety of leukocyte activities including activation and apoptosis. However, the uropod takes shape in neutrophils, monocytes, and natural killer cells, and the formation of this cell protrusion seems to exert an important role in immune interactions. In fact, the polarization sites of leukocytes are involved in a complex cross-talk between cells and extracellular matrix components, and a number of receptors and counter-receptors crowd in the contact sites to allow efficient cell-to-cell or cell-substrate interaction. The membrane/cytoskeleton interaction plays a crucial role in tuning these activities and in "predisposing" leukocytes to their function through the acquisition of a polarized phenotype. This review is focused on the mechanisms underlying the formation of the leukocyte uropod, the role of cytoskeleton in defining its structure and function, and the involvement of the uropod in the complex interplay between immune cells.
细胞极性的获得是白细胞迁移、激活和凋亡的关键要求。白细胞的极化涉及形成两个不同的极：前沿——细胞与底物的附着位点，允许细胞进行定向运动——而在相对的一侧，是尾足——主要参与细胞间相互作用以及包括激活和凋亡在内的多种白细胞活动。然而，尾足在中性粒细胞、单核细胞和自然杀伤细胞中形成，并且这种细胞突起的形成似乎在免疫相互作用中发挥重要作用。事实上，白细胞的极化位点参与了细胞与细胞外基质成分之间复杂的相互作用，并且许多受体和反受体聚集在接触位点，以实现有效的细胞间或细胞与底物的相互作用。膜/细胞骨架相互作用在调节这些活动以及通过获得极化表型使白细胞“倾向于”其功能方面起着关键作用。本综述聚焦于白细胞尾足形成的潜在机制、细胞骨架在定义其结构和功能中的作用，以及尾足在免疫细胞复杂相互作用中的参与情况。
