| 1. |
- Kurimoto, Eiji, et al.
(författare)
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Crystal structure of human proteasome assembly chaperone PAC4 involved in proteasome formation
- 2017
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Ingår i: Protein Science. - : WILEY. - 0961-8368 .- 1469-896X. ; 26:5, s. 1080-1085
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Tidskriftsartikel (refereegranskat)abstract
- The 26S proteasome is a large protein complex, responsible for degradation of ubiquinated proteins in eukaryotic cells. Eukaryotic proteasome formation is a highly ordered process that is assisted by several assembly chaperones. The assembly of its catalytic 20S core particle depends on at least five proteasome-specific chaperones, i.e., proteasome-assembling chaperons 1-4 (PAC1-4) and proteasome maturation protein (POMP). The orthologues of yeast assembly chaperones have been structurally characterized, whereas most mammalian assembly chaperones are not. In the present study, we determined a crystal structure of human PAC4 at 1.90-angstrom resolution. Our crystallographic data identify a hydrophobic surface that is surrounded by charged residues. The hydrophobic surface is complementary to that of its binding partner, PAC3. The surface also exhibits charge complementarity with the proteasomal 4-5 subunits. This will provide insights into human proteasome-assembling chaperones as potential anticancer drug targets.
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| 2. |
- Mitsueda, Asako, et al.
(författare)
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Development of a Novel Nanoparticle by Dual Modification With the Pluripotential Cell-Penetrating Peptide PepFect6 for Cellular Uptake, Endosomal Escape, and Decondensation of an siRNA Core Complex
- 2013
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Ingår i: Biopolymers. - : Wiley. - 0006-3525 .- 1097-0282. ; 100:6, s. 698-704
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Tidskriftsartikel (refereegranskat)abstract
- Development of novel devices for effective nucleotide release from nanoparticles is required to improve the functionality of nonviral delivery systems, because decondensation of nucleotide/polycation complexes is considered as a key step for cytoplasmic delivery of nucleotides. Previously, PepFect6 (PF6) comprised chloroquine analog moieties and a stearylated cell-penetrating peptide to facilitate endosomal escape and cellular uptake, respectively, was developed as a device for efficient siRNA delivery. As PF6 contains bulky chloroquine analog moieties, the polyplexes are expected to be loose structure, which facilitates decondensation. In the present study, siRNA was electrostatically condensed by PF6, and the PF6/siRNA complexes were coated with lipid membranes. The surface of the nanoparticles encapsulating the PF6/siRNA core (PF6-NP) was modified with PF6 for endosomal escape (PF6/PF6-NP). The RNAi effect of PF6/PF6-NP was compared with those of stearylated cell-penetrating peptide octaarginine (R8)-modified PF6-NP, R8-modified nanoparticles encapsulating the R8/siRNA core (R8-NP) and PF6-modified R8-NP. Nanoparticles encapsulating the PF6 polyplex, especially PF/PF-NP, showed a significant knockdown effect on luciferase activity of B16-F1 cells stably expressing luciferase. siRNA was widely distributed within the cytoplasm after transfection of the nanoparticles encapsulating the PF6 polyplex, while siRNA encapsulated in the R8-presenting nanoparticles was localized within the nuclei. Thus, the siRNA distribution was dependent on the manner of peptide-modification. In conclusion, we have successfully developed PF6/PF6-NP exhibiting a potent RNAi effect resulting from high cellular uptake, efficient endosomal escape and decondensation of the polyplexes based on the multifunctional cell penetrating peptide PF6. PF6 is therefore a useful pluripotential device for siRNA delivery. © 2013 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 100: 698-704, 2013.
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