Francis C L, Ryan T A, Jones B D, Smith S J, Falkow S
Department of Microbiology and Immunology, Stanford University, California 94305.
Nature. 1993 Aug 12;364(6438):639-42. doi: 10.1038/364639a0.
Ruffles are specialized plasma membrane ultrastructures of mammalian cells though to be integral to growth, development and locomotion. Induced by growth factors, mitogens or oncogene expression, ruffles are sites of filamentous actin rearrangement and are temporally associated with enhanced pinocytosis. But the function of ruffles, their mechanism of induction and their role in pinocytosis are not understood. We have observed formation of structures resembling ruffles associated with the site of entry of invasive Salmonella typhimurium. Here we report that ruffles elicited by invasive Salmonella directly mediate internalization of non-invasive bacteria in a macropinocytotic fashion, a phenomenon we term 'passive entry'. Furthermore, ruffles induced in the absence of Salmonella also facilitate passive entry. We present evidence that ruffles, common to many signalling events, comprise the macropinocytotic machinery mediating pinocytosis and are subverted by Salmonella so as to enter mammalian cells.
微绒毛是哺乳动物细胞特化的质膜超微结构，被认为对生长、发育和运动至关重要。由生长因子、有丝分裂原或癌基因表达诱导产生，微绒毛是丝状肌动蛋白重排的位点，并且在时间上与增强的胞饮作用相关。但是微绒毛的功能、它们的诱导机制以及它们在胞饮作用中的作用尚不清楚。我们观察到与侵袭性鼠伤寒沙门氏菌进入位点相关的类似微绒毛结构的形成。在此我们报告，侵袭性沙门氏菌引发的微绒毛以巨胞饮方式直接介导非侵袭性细菌的内化，我们将这一现象称为“被动进入”。此外，在没有沙门氏菌的情况下诱导产生的微绒毛也促进被动进入。我们提供的证据表明，许多信号事件共有的微绒毛构成了介导胞饮作用的巨胞饮机制，并且被沙门氏菌利用以进入哺乳动物细胞。
