Rqc1 and Ltn1 Prevent C-terminal Alanine-Threonine Tail (CAT-tail)-induced Protein Aggregation by Efficient Recruitment of Cdc48 on Stalled 60S Subunits.

ABSTRACT: Protein homeostasis is maintained by quality control mechanisms that detect and eliminate deficient translation products. Cytosolic defective proteins can arise from translation of aberrant mRNAs lacking a termination codon (NonStop) or containing a sequence that blocks translation elongation (No-Go), which results in translational arrest. Stalled ribosomes are dissociated, aberrant mRNAs are degraded by the cytoplasmic exosome, and the nascent peptides remaining in stalled 60S exit tunnels are detected by the ribosome-bound quality control complex (RQC) composed of Ltn1, Rqc1, Rqc2, and Cdc48. Whereas Ltn1 polyubiquitylates these nascent peptides, Rqc2 directs the addition of C-terminal alanine-threonine tails (CAT-tails), and a Cdc48 hexamer is recruited to extract the nascent peptides,

SUBMITTER: Defenouillere Q 

PROVIDER: S-EPMC4933273 | biostudies-literature | 2016 Jun

REPOSITORIES: biostudies-literature