Hart S L, Knight A M, Harbottle R P, Mistry A, Hunger H D, Cutler D F, Williamson R, Coutelle C
Department of Biochemistry and Molecular Genetics, St. Mary's Hospital Medical School, London, United Kingdom.
J Biol Chem. 1994 Apr 29;269(17):12468-74.
Ligands that bind mammalian cell surface integrins with high affinity can mediate cellular internalization. We show that particles of the bacteriophage fd that display the cyclic integrin-binding peptide sequence GGCRGDMFGC in a proportion of their major coat protein subunits bind to cells and are efficiently internalized. In the displayed peptide the conformation of the RGD motif is restricted within a hairpin loop formed by a disulfide bridge between the 2 cysteine residues. Cellular internalization of phage was demonstrated by confocal and non-confocal immunofluorescence microscopy of tissue-cultured cells incubated with phage particles. The phage were contained in juxtanuclear vesicles in the same serial sections as transferrin receptor but were not colocalized with the cell surface marker alkaline phosphatase. Cell binding and internalization was inhibited by preincubation of cells with the integrin-binding peptide GRGDSP, whereas the control peptide GRGESP had no inhibitory effect. These results indicate that cyclic integrin-binding peptides can be used to target and enter cells and that it should be possible to exploit such peptides for the introduction of DNA, drugs, or other macromolecules.
能与哺乳动物细胞表面整合素高亲和力结合的配体可介导细胞内化。我们发现，在其主要衣壳蛋白亚基的一定比例中展示环状整合素结合肽序列GGCRGDMFGC的噬菌体fd颗粒可与细胞结合并有效内化。在展示的肽中，RGD基序的构象被限制在由两个半胱氨酸残基之间的二硫键形成的发夹环内。通过对用噬菌体颗粒孵育的组织培养细胞进行共聚焦和非共聚焦免疫荧光显微镜观察，证实了噬菌体的细胞内化。在与转铁蛋白受体相同的连续切片中，噬菌体存在于核周小泡中，但不与细胞表面标志物碱性磷酸酶共定位。用整合素结合肽GRGDSP预孵育细胞可抑制细胞结合和内化，而对照肽GRGESP则无抑制作用。这些结果表明，环状整合素结合肽可用于靶向和进入细胞，并且利用此类肽引入DNA、药物或其他大分子应该是可行的。
