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From Proteopedia
Cryo-EM structure of human Dicer and its complexes with a pre-miRNA substrate
Structural highlights
FunctionTRBP2_HUMAN Required for formation of the RNA induced silencing complex (RISC). Component of the RISC loading complex (RLC), also known as the micro-RNA (miRNA) loading complex (miRLC), which is composed of DICER1, EIF2C2/AGO2 and TARBP2. Within the RLC/miRLC, DICER1 and TARBP2 are required to process precursor miRNAs (pre-miRNAs) to mature miRNAs and then load them onto EIF2C2/AGO2. EIF2C2/AGO2 bound to the mature miRNA constitutes the minimal RISC and may subsequently dissociate from DICER1 and TARBP2. May also play a role in the production of short interfering RNAs (siRNAs) from double-stranded RNA (dsRNA) by DICER1. Binds to the HIV-1 TAR RNA which is located in the long terminal repeat (LTR) of HIV-1, and stimulates translation of TAR-containing RNAs. This is achieved in part at least by binding to and inhibiting EIF2AK2/PKR, thereby reducing phosphorylation and inhibition of EIF2S1/eIF-2-alpha. May also promote translation of TAR-containing RNAs independently of EIF2AK2/PKR.[1] [2] [3] [4] [5] [6] [7] [8] [9] Publication Abstract from PubMedHuman Dicer (hDicer) is a multi-domain protein belonging to the RNase III family. It plays pivotal roles in small RNA biogenesis during the RNA interference (RNAi) pathway by processing a diverse range of double-stranded RNA (dsRNA) precursors to generate approximately 22 nt microRNA (miRNA) or small interfering RNA (siRNA) products for sequence-directed gene silencing. In this work, we solved the cryoelectron microscopy (cryo-EM) structure of hDicer in complex with its cofactor protein TRBP and revealed the precise spatial arrangement of hDicer's multiple domains. We further solved structures of the hDicer-TRBP complex bound with pre-let-7 RNA in two distinct conformations. In combination with biochemical analysis, these structures reveal a property of the hDicer-TRBP complex to promote the stability of pre-miRNA's stem duplex in a pre-dicing state. These results provide insights into the mechanism of RNA processing by hDicer and illustrate the regulatory role of hDicer's N-terminal helicase domain. Cryo-EM Structure of Human Dicer and Its Complexes with a Pre-miRNA Substrate.,Liu Z, Wang J, Cheng H, Ke X, Sun L, Zhang QC, Wang HW Cell. 2018 May 17;173(5):1191-1203.e12. doi: 10.1016/j.cell.2018.03.080. Epub, 2018 Apr 26. PMID:29706542[10] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. Loading citation details.. Citations No citations found See AlsoReferences
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Categories: Homo sapiens | Large Structures | Cheng H | Ke X | Liu Z | Sun L | Wang H-W | Wang J | Zhang QC