de Carvalho Tecia M U, Barrias Emile S, de Souza Wanderley
Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Centro de Ciência da Saúde, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil ; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens e Centro Nacional de Bioimagens-CENABIO, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil.
Instituto Nacional de Metrologia, Qualidade e Tecnologia-Inmetro Rio de Janeiro, Brazil.
Front Physiol. 2015 Apr 9;6:106. doi: 10.3389/fphys.2015.00106. eCollection 2015.
Among the various endocytic mechanisms in mammalian cells, macropinocytosis involves internalization of large amounts of plasma membrane together with extracellular medium, leading to macropinosome formation. These structures are formed when plasma membrane ruffles are assembled after actin filament rearrangement. In dendritic cells, macropinocytosis has been reported to play a role in antigen presentation. Several intracellular pathogens are internalized by host cells via multiple endocytic pathways and macropinocytosis has been described as an important entry site for various organisms. Some bacteria, such as Legionella pneumophila, as well as various viruses, use this pathway to penetrate and subvert host cells. Some protozoa, which are larger than bacteria and virus, can also use this pathway to invade host cells. As macropinocytosis is characterized by the formation of large uncoated vacuoles and is triggered by various signaling pathways, which is similar to what occurs during the formation of the majority of parasitophorous vacuoles, it is believed that this phenomenon may be more widely used by parasites than is currently appreciated. Here we review protozoa host cell invasion via macropinocytosis.
在哺乳动物细胞的各种内吞机制中，巨吞饮作用涉及大量质膜与细胞外介质的内化，导致巨吞饮体的形成。当肌动蛋白丝重排后质膜褶皱组装时，这些结构就会形成。在树突状细胞中，据报道巨吞饮作用在抗原呈递中发挥作用。几种细胞内病原体通过多种内吞途径被宿主细胞内化，巨吞饮作用被描述为各种生物体的重要进入位点。一些细菌，如嗜肺军团菌，以及各种病毒，利用这条途径穿透并破坏宿主细胞。一些比细菌和病毒更大的原生动物也可以利用这条途径侵入宿主细胞。由于巨吞饮作用的特征是形成大的无包被液泡，并由各种信号通路触发，这与大多数寄生泡形成过程中发生的情况相似，因此人们认为这种现象可能比目前所认识到的更广泛地被寄生虫利用。在这里，我们综述原生动物通过巨吞饮作用入侵宿主细胞的情况。
