Abstract
Decapping of eukaryotic messenger RNAs (mRNAs) occurs after they have undergone deadenylation, but how these processes are coordinated is poorly understood. In this study, we report that Drosophila melanogaster HPat (homologue of Pat1), a conserved decapping activator, interacts with additional decapping factors (e.g., Me31B, the LSm1-7 complex, and the decapping enzyme DCP2) and with components of the CCR4-NOT deadenylase complex. Accordingly, HPat triggers deadenylation and decapping when artificially tethered to an mRNA reporter. These activities reside, unexpectedly, in a proline-rich region. However, this region alone cannot restore decapping in cells depleted of endogenous HPat but also requires the middle (Mid) and the very C-terminal domains of HPat. We further show that the Mid and C-terminal domains mediate HPat recruitment to target mRNAs. Our results reveal an unprecedented role for the proline-rich region and the C-terminal domain of metazoan HPat in mRNA decapping and suggest that HPat is a component of the cellular mechanism that couples decapping to deadenylation in vivo.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Cells, Cultured
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DEAD-box RNA Helicases / genetics
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DEAD-box RNA Helicases / metabolism
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Drosophila Proteins / genetics
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Drosophila Proteins / metabolism*
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Drosophila melanogaster / genetics
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Drosophila melanogaster / metabolism*
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Endoribonucleases / genetics
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Endoribonucleases / metabolism
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Homeodomain Proteins / genetics
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Homeodomain Proteins / metabolism
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Humans
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Molecular Sequence Data
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Protein Structure, Tertiary
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RNA Caps / metabolism*
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RNA Stability
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RNA, Messenger / genetics
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RNA, Messenger / metabolism*
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RNA-Binding Proteins / genetics
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RNA-Binding Proteins / metabolism*
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Ribonucleases / genetics
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Ribonucleases / metabolism
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Ribonucleoproteins, Small Nuclear / genetics
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Ribonucleoproteins, Small Nuclear / metabolism
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Sequence Alignment
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Transcription Factors / genetics
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Transcription Factors / metabolism
Substances
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Drosophila Proteins
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Edc3 protein, Drosophila
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Homeodomain Proteins
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Lcp2 protein, Drosophila
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Patr-1 protein, Drosophila
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RNA Caps
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RNA, Messenger
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RNA-Binding Proteins
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Recombinant Fusion Proteins
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Ribonucleoproteins, Small Nuclear
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Transcription Factors
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mRNA decapping enzymes
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Me31B protein, Drosophila
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CCR4 protein, Drosophila
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Endoribonucleases
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Ribonucleases
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DEAD-box RNA Helicases