The R2T(P) complex orchestrates the SHQ1 driven early steps of box H/ACA snoRNP maturation
Abstract
The chaperones RuvBL1 and RuvBL2 are members of the AAA+ ATPase family and participate in diverse cellular processes, including DNA repair, transcriptional regulation, and assembly of macromolecular complexes such as snoRNPs. The biogenesis of box H/ACA snoRNPs additionally requires the assembly factor SHQ1. These protein-RNA complexes are essential for ribosome biogenesis and telomerase stability and are linked to diseases such as dyskeratosis congenita and cancer. Despite detailed knowledge of mature complexes, their assembly mechanisms and how they can be modulated remain unclear. We characterize a trimeric interaction between SHQ1 and RuvBL1:RuvBL2, providing insight into early maturation of the protein-only precursor of box H/ACA snoRNPs. SHQ1 binds the flexible domain II of RuvBL1:RuvBL2, corresponding to the dodecamerization interface, suggesting disruption of this interface and promotion of hexamer formation. We further purified a complex containing RuvBL1:RuvBL2, SHQ1, and DKC1, the catalytic component of H/ACA snoRNPs and a client of SHQ1. This demonstrates that SHQ1 and DKC1 can simultaneously associate with RuvBL1:RuvBL2, potentially facilitating DKC1 release and subsequent snoRNA binding. Additionally, we identified a direct interaction between SHQ1 and RPAP3, a co-chaperone of RuvBL1:RuvBL2 (within the R2TP). Hence, RPAP3 may be responsible for recruiting SHQ1:DKC1 to hexameric RuvBL1:RuvBL2 and/or assist in the AAA+ mediated dissociation of the dimer. Since SHQ1 shares a domain with PIH1D1, an integral member of the R2TP complex, our findings suggest that early H/ACA snoRNP maturation may involve the R2T instead of the previously proposed R2TP complex.
Related
- PPR9 mediates mitochondrial nad transcript maturation required for complex I biogenesis and early plant development in Arabidopsis.
- SARS-CoV-2 maturation driven by a mechano-active nucleocapsid-RNA condensate
- Sequential division of labor between PAXX and XLF drives NHEJ synaptic complex stability and maturation
- RNA helicase Drs1 gates 25S rRNA domain III incorporation during early nucleolar pre-60S maturation
- New pathogenic ZNHIT3 variants causing fetal hydrops and lethality disrupt snoRNP assembly
BibTeX
@misc{busse2026r2tp,
title = {{The R2T(P) complex orchestrates the SHQ1 driven early steps of box H/ACA snoRNP maturation}},
author = {Philipp Busse and Ana Paiva and Paulo Santo and Hugo Gizardin-Fredon and Carolina Cassona and Marie-Eve Chagot and Catarina Malta and Céline Verheggen and Hannah Oksannen and Sarah Butcher and Sarah Cianferani and Xavier Manival and Celia Plisson-Chastang and Edouard Bertrand and Pedro Sousa and Tiago Bandeiras},
howpublished = {HAL},
year = {2026},
month = jun,
doi = {10.64898/2026.05.30.726169},
url = {https://hal.science/hal-05779411v1},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - UNPB
TI - The R2T(P) complex orchestrates the SHQ1 driven early steps of box H/ACA snoRNP maturation
AU - Philipp Busse
AU - Ana Paiva
AU - Paulo Santo
AU - Hugo Gizardin-Fredon
AU - Carolina Cassona
AU - Marie-Eve Chagot
AU - Catarina Malta
AU - Céline Verheggen
AU - Hannah Oksannen
AU - Sarah Butcher
AU - Sarah Cianferani
AU - Xavier Manival
AU - Celia Plisson-Chastang
AU - Edouard Bertrand
AU - Pedro Sousa
AU - Tiago Bandeiras
PY - 2026
DA - 2026/06/02
PB - HAL
DO - 10.64898/2026.05.30.726169
UR - https://hal.science/hal-05779411v1
AB - The chaperones RuvBL1 and RuvBL2 are members of the AAA+ ATPase family and participate in diverse cellular processes, including DNA repair, transcriptional regulation, and assembly of macromolecular complexes such as snoRNPs. The biogenesis of box H/ACA snoRNPs additionally requires the assembly factor SHQ1. These protein-RNA complexes are essential for ribosome biogenesis and telomerase stability and are linked to diseases such as dyskeratosis congenita and cancer. Despite detailed knowledge of mature complexes, their assembly mechanisms and how they can be modulated remain unclear. We characterize a trimeric interaction between SHQ1 and RuvBL1:RuvBL2, providing insight into early maturation of the protein-only precursor of box H/ACA snoRNPs. SHQ1 binds the flexible domain II of RuvBL1:RuvBL2, corresponding to the dodecamerization interface, suggesting disruption of this interface and promotion of hexamer formation. We further purified a complex containing RuvBL1:RuvBL2, SHQ1, and DKC1, the catalytic component of H/ACA snoRNPs and a client of SHQ1. This demonstrates that SHQ1 and DKC1 can simultaneously associate with RuvBL1:RuvBL2, potentially facilitating DKC1 release and subsequent snoRNA binding. Additionally, we identified a direct interaction between SHQ1 and RPAP3, a co-chaperone of RuvBL1:RuvBL2 (within the R2TP). Hence, RPAP3 may be responsible for recruiting SHQ1:DKC1 to hexameric RuvBL1:RuvBL2 and/or assist in the AAA+ mediated dissociation of the dimer. Since SHQ1 shares a domain with PIH1D1, an integral member of the R2TP complex, our findings suggest that early H/ACA snoRNP maturation may involve the R2T instead of the previously proposed R2TP complex.
ER -