Author/Authors :
Andrey L. Karamyshev، نويسنده , , Anna E. Patrick، نويسنده , , Zemfira N. Karamysheva، نويسنده , , Dustin S. Griesemer، نويسنده , , Henry Hudson، نويسنده , , Sandra Tjon-Kon-Sang، نويسنده , , IngMarie Nilsson، نويسنده , , Hendrik Otto، نويسنده , , Qinghua Liu، نويسنده , , Sabine Rospert، نويسنده , , Gunnar von Heijne، نويسنده , , Arthur E. Johnson، نويسنده , , Philip J. Thomas and John F. Hunt، نويسنده ,
Abstract :
Misfolded proteins are often cytotoxic, unless cellular systems prevent their accumulation. Data presented here uncover a mechanism by which defects in secretory proteins lead to a dramatic reduction in their mRNAs and protein expression. When mutant signal sequences fail to bind to the signal recognition particle (SRP) at the ribosome exit site, the nascent chain instead contacts Argonaute2 (Ago2), and the mutant mRNAs are specifically degraded. Severity of signal sequence mutations correlated with increased proximity of Ago2 to nascent chain and mRNA degradation. Ago2 knockdown inhibited degradation of the mutant mRNA, while overexpression of Ago2 or knockdown of SRP54 promoted degradation of secretory protein mRNA. The results reveal a previously unappreciated general mechanism of translational quality control, in which specific mRNA degradation preemptively regulates aberrant protein production (RAPP).
