Role of Rck-Pat1b binding in assembly of processing-bodies.
The DEAD box RNA helicase Rck and the scaffold protein Pat1b participate in controlling gene expression at the post-transcriptional level by suppressing mRNA translation and promoting mRNA decapping. In addition, both proteins are required for the assembly of processing (P)-bodies, cytoplasmic foci that contain stalled mRNAs and numerous components of ... the mRNA decay machinery. The C-terminal RecA-like domain of Rck interacts with the N-terminal acidic domain of Pat1b. Here, we identified point mutations in human Rck and Pat1b that prevent the two proteins from binding to each other. By analyzing interaction-deficient mutants in combination with knockdown and rescue strategies in human HeLa cells, we found that Pat1b assembles P-bodies and suppresses expression of tethered mRNAs in the absence of Rck binding. In contrast, Rck requires the Pat1b-binding site in order to promote P-body assembly and associate with the decapping enzyme Dcp2 as well as Ago2 and TNRC6A, two core components of the RNA-induced silencing complex. Our data indicate that P-body assembly occurs in a step-wise manner, where Rck participates in the initial suppression of mRNA translation, whereas Pat1b in a second step triggers P-body assembly and promotes mRNA decapping.
Mesh Terms:
DEAD-box RNA Helicases, DNA-Binding Proteins, Endoribonucleases, Evolution, Molecular, Gene Expression Regulation, HEK293 Cells, HeLa Cells, Humans, Point Mutation, Protein Binding, Proto-Oncogene Proteins, RNA Stability, RNA, Messenger, RNA, Small Interfering
DEAD-box RNA Helicases, DNA-Binding Proteins, Endoribonucleases, Evolution, Molecular, Gene Expression Regulation, HEK293 Cells, HeLa Cells, Humans, Point Mutation, Protein Binding, Proto-Oncogene Proteins, RNA Stability, RNA, Messenger, RNA, Small Interfering
RNA Biol
Date: Apr. 01, 2013
PubMed ID: 23535175
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