CNRS, UMR 7203, Laboratoire des Biomolécules, Groupe N. J. Conté, Paris, France.
Int J Biochem Cell Biol. 2012 Jun;44(6):869-75. doi: 10.1016/j.biocel.2012.02.010. Epub 2012 Feb 23.
Cellular uptake of vector peptides used for internalization of hydrophilic molecules into cells is known to follow two different pathways: direct translocation of the plasma membrane and internalization by endocytosis followed by release into the cytosol. These pathways differ in their energy dependence. The first does not need metabolic energy while the second requires metabolic energy. Herein we used erythrocytes and plasma membrane vesicles to study membrane perturbations induced by the cell penetrating peptide penetratin. The results show that cell penetrating peptides are able to be internalized by two metabolic energy-independent pathways: direct crossing of the plasma membrane and endocytosis-like mechanisms. The last mechanism involves the induction of membrane negative curvature resulting in invaginations that mimic the endosomal uptake in the absence of ATP. This new mechanism called "physical endocytosis" or "self-induced endocytosis" might explain different data concerning the independence or dependence on metabolic energy during cellular uptake and reveals the autonomous capacity of peptides to induce their internalization.
细胞对用于将亲水分子内吞到细胞内的载体肽的摄取，已知遵循两种不同的途径：直接穿过质膜的转位和通过胞吞作用内化，随后释放到细胞质溶胶中。这些途径在能量依赖性上有所不同。前者不需要代谢能量，而后者需要代谢能量。本文中，我们使用红细胞和质膜囊泡来研究细胞穿透肽 penetratin 诱导的膜扰动。结果表明，细胞穿透肽能够通过两种非代谢能量依赖的途径被内吞：直接穿过质膜和胞吞样机制。最后一种机制涉及诱导膜负曲率，从而产生内陷，模拟无 ATP 时的内吞体摄取。这种新的机制称为“物理胞吞”或“自诱导内吞”，可能解释了关于细胞摄取过程中对代谢能量的独立性或依赖性的不同数据，并揭示了肽自主诱导其内化的能力。
