A specific type of Argonaute phosphorylation regulates binding to microRNAs during C. elegans development

Cell Rep. 2022 Dec 13;41(11):111822. doi: 10.1016/j.celrep.2022.111822.


Argonaute proteins are at the core of the microRNA-mediated gene silencing pathway essential for animals. In C. elegans, the microRNA-specific Argonautes ALG-1 and ALG-2 regulate multiple processes required for proper animal developmental timing and viability. Here we identified a phosphorylation site on ALG-1 that modulates microRNA association. Mutating ALG-1 serine 642 into a phospho-mimicking residue impairs microRNA binding and causes embryonic lethality and post-embryonic phenotypes that are consistent with alteration of microRNA functions. Monitoring microRNA levels in alg-1 phosphorylation mutant animals shows that microRNA passenger strands increase in abundance but are not preferentially loaded into ALG-1, indicating that the miRNA binding defects could lead to microRNA duplex accumulation. Our genetic and biochemical experiments support protein kinase A (PKA) KIN-1 as the putative kinase that phosphorylates ALG-1 serine 642. Our data indicate that PKA triggers ALG-1 phosphorylation to regulate its microRNA association during C. elegans development.

Keywords: AGO; ALG-1; CP: Developmental biology; CP: Molecular biology; KIN-1; PKA; gene regulation; miRISC; microRNA duplex; microRNA passenger strand; post-translational modification; protein kinase A.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Argonaute Proteins / genetics
  • Argonaute Proteins / metabolism
  • Caenorhabditis elegans / metabolism
  • Caenorhabditis elegans Proteins* / metabolism
  • MicroRNAs* / genetics
  • MicroRNAs* / metabolism
  • Phosphorylation
  • RNA-Binding Proteins / metabolism
  • Serine / metabolism


  • Argonaute Proteins
  • Caenorhabditis elegans Proteins
  • MicroRNAs
  • RNA-Binding Proteins
  • Serine
  • ALG-1 protein, C elegans
  • ALG-2 protein, C elegans