Pathway for polyarginine entry into mammalian cell
Pathway for polyarginine entry into mammalian cell
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DOI：
10.1021/bi035933x
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发表时间：
2004-03-09
期刊：
影响因子：
2.9
通讯作者：
Raines, RT
中科院分区：
文献类型：
--
作者：
Fuchs, SM;Raines, RT
被称为蛋白转导结构域（PTD）的阳离子肽提供了将分子递送到哺乳动物细胞中的手段。在这里，九精氨酸（R-9），最有效的已知PTD，用于阐明PTD内化的途径。虽然R-9在细胞固定时存在于胞质溶胶和核仁中，但该肽仅在活细胞的内吞囊泡中观察到。与囊泡标记物的共定位研究证实，PTDs是通过内吞作用而不是通过穿过质膜内化的。R-9不能进入缺乏硫酸乙酰肝素（HS）的活细胞表明，与HS的结合是PTD内化所必需的。这一发现与R-9对肝素的高亲和力（Kd = 109 nM）一致。最后，R-9显示促进脂质体的渗漏，但仅在高肽：脂质比下。这些和其他数据表明，PTD介导的分子向活哺乳动物细胞中的递送涉及（1）与细胞表面HS结合，（2）通过内吞作用摄取，（3）HS降解后释放，和（4）从内吞囊泡中泄漏。
Cationic peptides known as protein transduction domains (PTDs) provide a means to deliver molecules into mammalian cells. Here, nonaarginine (R-9), the most efficacious of known PTDs, is used to elucidate the pathway for PTD internalization. Although R-9 is found in the cytosol as well as the nucleolus when cells are fixed, this peptide is observed only in the endocytic vesicles of live cells. Colocalization studies with vesicular markers confirm that PTDs are internalized by endocytosis rather than by crossing the plasma membrane. The inability of R-9 to enter living cells deficient in heparan sulfate (HS) suggests that binding to HS is necessary for PTD internalization. This finding is consistent with the high affinity of R-9 for heparin (K-d = 109 nM). Finally, R-9 is shown to promote the leakage of liposomes but only at high peptide:lipid ratios. These and other data indicate that the PTD-mediated delivery of molecules into live mammalian cells involves (1) binding to cell surface HS, (2) uptake by endocytosis, (3) release upon HS degradation, and (4) leakage from endocytic vesicles.