Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10748254 | Biochemical and Biophysical Research Communications | 2016 | 5 Pages |
Abstract
The amino-nucleoside antibiotic, puromycin, acts by covalently linking to elongating polypeptide chains on ribosomes to generate prematurely terminated immature polypeptides. The trafficking of puromycin-conjugated (puromycylated) immature polypeptides within cell has, however, remained elusive. In this study, using O-propargyl-puromycin (OP-Puro), the distribution of puromycylated polypeptides was assessed in HeLa cells by click chemistry. Under standard culture conditions, OP-Puro signals were detected in the cytoplasm and nucleus with the highest concentrations in the nucleolus. Intriguingly, when proteasome activities were aborted using MG132, OP-Puro signals began to accumulate at promyelocytic leukemia nuclear bodies (PML-NBs) in addition to the nucleolus. We also found promiscuous association of OP-Puro signals with SUMO-2/3 and ubiquitin at PML-NBs, but not at the nucleolus, during abortive proteasome activities. This study reveals a previously unknown distribution of OP-Puro that argues for a nuclear function in regulating immature protein homeostasis.
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Authors
Naoki Uozumi, Hotaru Matsumoto, Hisato Saitoh,