Supramolecular protein assemblies in the nucleus of human cells.
Genetically encoded supramolecular protein assemblies (SMPAs) are induced to form in living cells by combination of distinct self-assembly properties. A single fusion construct contains genes encoding the heavy chain (H) of human ferritin and the citrine fluorescent protein, the latter exposing a weak dimerization interface, as well as a nuclear localization signal. Upon expression in HeLa cells, in vivo confocal fluorescence and differential interference contrast imaging revealed extended SMPA structures exclusively in the nuclei. Assemblies were typically round and took alveolar, shell-like, or hybrid structure. Transmission electron microscopy revealed a crystalline packing. Site-specific mutagenesis of the citrine dimerization interface clarified the mechanism of SMPA formation. The constituent proteins retained their activity in iron binding and fluorescence emission, thus suggesting a general strategy for formation of synthetic cellular bodies with specific biochemical function.
Dept of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100 (Israel).
Giuliano
G
Bellapadrona
Michael
M
Elbaum
D002467:Cell Nucleus / Q000378:metabolism*; D005293:Ferritins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D018613:Microscopy, Confocal; D054730:Protein Interaction Domains and Motifs; D011506:Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics
D011506:Proteins; D011993:Recombinant Fusion Proteins; D005293:Ferritins
cellular bodies; protein crystals; protein-protein interactions; self-assembly