title: Intracellular protein delivery activity of peptides derived from insulin-like growth factor binding proteins 3 and 5.
abstract: Insulin-like growth factor binding proteins (IGFBPs) have various IGF-independent cellular activities, including receptor-independent cellular uptake followed by transcriptional regulation, although mechanisms of cellular entry remain unclear. Herein, we focused on their receptor-independent cellular entry mechanism in terms of protein transduction domain (PTD) activity, which is an emerging technique useful for clinical applications. The peptides of 18 amino acid residues derived from IGFBP-3 and IGFBP-5, which involve heparin-binding regions, mediated cellular delivery of an exogenous protein into NIH3T3 and HeLa cells. Relative protein delivery activities of IGFBP-3/5-derived peptides were approximately 20-150% compared to that of the HIV-Tat peptide, a potent PTD. Heparin inhibited the uptake of the fusion proteins with IGFBP-3 and IGFBP-5, indicating that the delivery pathway is heparin-dependent endocytosis, similar to that of HIV-Tat. The delivery of GST fused to HIV-Tat was competed by either IGFBP-3 or IGFBP-5-derived synthetic peptides. Therefore, the entry pathways of the three PTDs are shared. Our data has shown a new approach for designing protein delivery systems using IGFBP-3/5 derived peptides based on the molecular mechanisms of IGF-independent activities of IGFBPs.
authors.affiliation: Division of Biophysics, International Graduate School of Arts and Sciences, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
authors.forename: Natsuko
authors.initials: N
authors.lastname: Goda
authors.forename: Takeshi
authors.initials: T
authors.lastname: Tenno
authors.forename: Kosuke
authors.initials: K
authors.lastname: Inomata
authors.forename: Masahiro
authors.initials: M
authors.lastname: Shirakawa
authors.forename: Toshiki
authors.initials: T
authors.lastname: Tanaka
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Hiroaki
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D016503:Drug Delivery Systems / Q000379:methods*; D005982:Glutathione Transferase / Q000737:chemistry / Q000378:metabolism; D006367:HeLa Cells; D006493:Heparin / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D018975:Insulin-Like Growth Factor Binding Protein 5 / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D051379:Mice; D008954:Models, Biological; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D010446:Peptide Fragments / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D011993:Recombinant Fusion Proteins / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D000077022:Survivin; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000378:metabolism
chemical_list: D051017:Apoptosis Regulatory Proteins; C512124:HIV-TAT-survivin (T34A) protein; D018972:Insulin-Like Growth Factor Binding Protein 3; D018975:Insulin-Like Growth Factor Binding Protein 5; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D000077022:Survivin; D054322:tat Gene Products, Human Immunodeficiency Virus; D006493:Heparin; D005982:Glutathione Transferase