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Premature translation termination products are substrates for the rapidly degraded polypeptide pathway
Author(s) -
Lacsina Joshua Rene,
Liu Xiongfei,
Nicchitta Christopher V.
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.839.2
Subject(s) - puromycin , translation (biology) , immunoprecipitation , protein biosynthesis , stop codon , chemistry , microbiology and biotechnology , biochemistry , biology , messenger rna , amino acid , gene
In mammalian cells, nearly one‐third of all newly synthesized polypeptides are rapidly degraded (t 1/2 = 10 min), however it is unclear what mechanisms govern access to the rapidly degraded polypeptide (RDP) pathway. The objective of this study is to determine if the products of premature translational termination are RDPs. To elicit premature termination, cells were treated with the aminoacyl‐tRNA analog, puromycin. Puromycin‐treated cells were labeled with [ 35 S]‐Met, and puromycin‐labeled translation products were recovered by immunoprecipitation with an anti‐puromycin antibody. [ 35 S]‐Met pulse‐chase studies demonstrated that peptidyl‐puromycins are polyubiquitinated and rapidly degraded in a proteasome‐dependent manner; proteasomal inhibition led to a 2.3‐fold increase in radiolabeled peptidyl‐puromycins. These results demonstrate that premature translation termination products can serve as substrates for the RDP pathway. Our findings suggest that the nature of the translation termination event (premature vs. stop codon‐mediated) influences the stability of the nascent polypeptide. Supported by NIH grants F31GM086127, R01GM077382, and T32GM007171.