title: The protease-mediated nucleus shuttles of subnanometer gold quantum dots for real-time monitoring of apoptotic cell death.
abstract: Subnanometer photoluminescent gold quantum dots (GQDs) are functionalized with a peptide moiety that contains both nuclear export signal (NES) and nuclear localization signal (NLS) sequences. By taking advantage of its small size and great photostability, the functionalized GQDs are used to mimic the actions of nucleus shuttle proteins, especially of those activated during cell apoptotic death, to work as protease-mediated cytoplasm-nucleus shuttles for dynamic monitoring of apoptosis. The resulting construct demonstrates activation of the nuclear pore complex (NPC) of cells, for bidirectional transport between nucleus and cytoplasm. A caspase-3 recognition sequence (DEVD), placed within the NLS/NES peptide, serves as a proteolytic site for activated caspase-3. Upon the induction of apoptosis, the activated caspase-3 cleaves the functional peptide on GQDs resulting in changes of subcellular distribution of GQDs. Such changes can be quantified as a function of time, by the ratios of GQDs photoluminescence in nucleus to that in cytoplasm. As such, the NES-linker-DEVD-linker-NLS peptide enables the GQDs to function as molecular probes for the real-time monitoring of cellular apoptosis.
authors.affiliation: Center for Nanomedicine Research, National Health Research Institutes, 35 Keyan Road Zhunan, Miaoli, Taiwan.
authors.forename: Shu-Yi
authors.initials: SY
authors.lastname: Lin
authors.forename: Nai-Tzu
authors.initials: NT
authors.lastname: Chen
authors.forename: Shu-Pin
authors.initials: SP
authors.lastname: Sun
authors.forename: Jerry C
authors.initials: JC
authors.lastname: Chang
authors.forename: Yu-Chao
authors.initials: YC
authors.lastname: Wang
authors.forename: Chung-Shi
authors.initials: CS
authors.lastname: Yang
authors.forename: Leu-Wei
authors.initials: LW
authors.lastname: Lo
mesh_terms: D021581:Active Transport, Cell Nucleus; D000595:Amino Acid Sequence; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D005434:Flow Cytometry; D006046:Gold / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D018613:Microscopy, Confocal; D008958:Models, Molecular; D019913:Nuclear Localization Signals / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation; D045663:Quantum Dots; D019311:Staurosporine / Q000494:pharmacology; D013997:Time Factors
chemical_list: D019913:Nuclear Localization Signals; D006046:Gold; D053148:Caspase 3; D019311:Staurosporine