Rupert PB et al. (1998) Nat Struct Biol "A new DNA-binding motif in the Skn-1 binding domain-DNA complex."

Bowerman BA, Matthews BW, Rupert PB, Daughdrill GW

[Nat Struct Biol, 1998]

The DNA-binding domain of Skn-1, a developmental transcription factor that specifies mesoderm in C. elegans, is shown by X-ray crystallography to have a novel fold in which a compact, monomeric, four-helix unit organizes two DNA-contact elements. At the C-terminus, a helix extends from the domain to occupy the major groove of DNA in a manner similar to bZip proteins. Skn-1, however, lacks the leucine zipper found in all bZips. Additional contacts with the DNA are made by a short basic segment at the N-terminus of the domain, reminiscent of the 'homeodomain arm'.

Kuzuoglu-Ozturk D et al. (2012) Nucleic Acids Res "The Caenorhabditis elegans GW182 protein AIN-1 interacts with PAB-1 and subunits of the PAN2-PAN3 and CCR4-NOT deadenylase complexes."

Izaurralde E, Kuzuoglu-Ozturk D, Schmidt S, Huntzinger E

[Nucleic Acids Res, 2012]

GW182 family proteins are essential for miRNA-mediated gene silencing in animal cells. They are recruited to miRNA targets via interactions with Argonaute proteins and then promote translational repression and degradation of the miRNA targets. The human and Drosophila melanogaster GW182 proteins share a similar domain organization and interact with PABPC1 as well as with subunits of the PAN2-PAN3 and CCR4-NOT deadenylase complexes. The homologous proteins in Caenorhabditis elegans, AIN-1 and AIN-2, lack most of the domains present in the vertebrate and insect proteins, raising the question as to how AIN-1 and AIN-2 contribute to silencing. Here, we show that both AIN-1 and AIN-2 interact with Argonaute proteins through GW repeats in the middle region of the AIN proteins. However, only AIN-1 interacts with C. elegans and D. melanogaster PABPC1, PAN3, NOT1 and NOT2, suggesting that AIN-1 and AIN-2 are functionally distinct. Our findings reveal a surprising evolutionary plasticity of the GW182 protein interaction network and demonstrate that binding to PABPC1 and deadenylase complexes has been maintained throughout evolution, highlighting the significance of these interactions for silencing.