School of Chemistry and Molecular Biosciences, Australian Research Council Centre of Excellence for Integrative Legume Research, University of Queensland, St. Lucia, Queensland 4072, Australia.
Proc Natl Acad Sci U S A. 2010 Jul 20;107(29):12883-8. doi: 10.1073/pnas.1001085107. Epub 2010 Jun 21.
Endocytosis is a process by which extracellular material such as macromolecules can be incorporated into cells via a membrane-trafficking system. Although universal among eukaryotes, endocytosis has not been identified in Bacteria or Archaea. However, intracellular membranes are known to compartmentalize cells of bacteria in the phylum Planctomycetes, suggesting the potential for endocytosis and membrane trafficking in members of this phylum. Here we show that cells of the planctomycete Gemmata obscuriglobus have the ability to uptake proteins present in the external milieu in an energy-dependent process analogous to eukaryotic endocytosis, and that internalized proteins are associated with vesicle membranes. Occurrence of such ability in a bacterium is consistent with autogenous evolution of endocytosis and the endomembrane system in an ancestral noneukaryote cell.
内吞作用是一种通过膜运输系统将细胞外物质（如大分子）纳入细胞的过程。尽管在真核生物中普遍存在，但尚未在细菌或古菌中发现内吞作用。然而，已知在拟杆菌门的细菌中，细胞内的膜将其分隔开来，这表明该门的成员可能具有内吞作用和膜运输的能力。在这里，我们表明，暗球形菌属 Gemmata obscuriglobus 的细胞能够在能量依赖的过程中摄取存在于外部环境中的蛋白质，类似于真核内吞作用，并且内化的蛋白质与囊泡膜相关。这种能力在细菌中的出现与内吞作用和内共生起源的真核细胞的内膜系统的自主进化是一致的。
