Target binding triggers hierarchical phosphorylation of human Argonaute-2 to promote target release

Bibel, Brianna, Elkayam, Elad, Silletti, Steve, Komives, Elizabeth A, Joshua-Tor, Leemor (May 2022) Target binding triggers hierarchical phosphorylation of human Argonaute-2 to promote target release. eLife, 11. ISSN 2050-084X

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Abstract

Argonaute (Ago) proteins play a central role in post-transcriptional gene regulation through RNA interference (RNAi). Agos bind small RNAs (sRNAs) including small interfering RNAs (siRNAs) and microRNAs (miRNAs) to form the functional core of the RNA-induced silencing complex (RISC). The sRNA is used as a guide to target mRNAs containing either partially or fully complementary sequences, ultimately leading to downregulation of the corresponding proteins. It was previously shown that the kinase CK1α phosphorylates a cluster of residues in the eukaryotic insertion (EI) of Ago, leading to the alleviation of miRNA-mediated repression through an undetermined mechanism. We show that binding of miRNA-loaded human Ago2 to target RNA with complementarity to the seed and 3' supplementary regions of the miRNA primes the EI for hierarchical phosphorylation by CK1α. The added negative charges electrostatically promote target release, freeing Ago to seek out additional targets once it is dephosphorylated. The high conservation of potential phosphosites in the EI suggests that such a regulatory strategy may be a shared mechanism for regulating miRNA-mediated repression.

Item Type:	Paper
Subjects:	bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > argonaute proteins bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein expression > phosphorylation
CSHL Authors:	Joshua-Tor, Leemor Bibel, Brianna Elkayam, Elad
Communities:	CSHL labs > Joshua-Tor lab School of Biological Sciences > Publications
SWORD Depositor:	CSHL Elements
Depositing User:	CSHL Elements
Date:	31 May 2022
Date Deposited:	02 Jun 2022 15:48
Last Modified:	02 Jun 2022 15:48
URI:	https://repository.cshl.edu/id/eprint/40644

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