# Unveiling the Ro60-Ro52 complex

## TL;DR

The study shows that Ro60 and Ro52 proteins form a weak, temporary complex in the cytoplasm, linking RNA quality control with proteolysis.

## Contribution

The novel contribution is the experimental confirmation of a transient Ro60-Ro52 complex and its structural and functional implications.

## Key findings

- Ro60 and Ro52 form a weak transient complex in the cytoplasm with a Ka of ~3.7 x 10^6 M-1.
- The Ro60-Ro52 interaction involves Ro60 residues K133, W177, and L185, which are important for Ro60-YRNA binding.
- The complex formation bridges RNA quality control and intracellular proteolysis pathways.

## Abstract

The coexistence within a subcellular complex of inter-cellular proteins Ro60, responsible for preserving ncRNA quality, and Ro52, involved in intracellular proteolysis, has been a subject of ongoing debate. Employing molecular docking in tandem with experimental methods like Quartz Crystal Microbalance with Dissipation (QCM-D), Proximity Ligation Assay (PLA), and Indirect Immunofluorescence (IIF), we reveal the presence of Ro60 associating with Ro52 within the cytoplasm. This result unveils the formation of a weak transient complex with a Ka ≈ (3.7 ± 0.3) x 106 M-1, where the toroid-shaped Ro60 structure interacts with the Ro52's Fc receptor, aligning horizontally within the PRY-SPRY domains of the Ro52's homodimer. The stability of this complex relies on the interaction between Ro52 chain A and specific Ro60 residues, such as K133, W177, or L185, vital in the Ro60-YRNA bond. These findings bridge the role of Ro60 in YRNA management with Ro52's function in intracellular proteolysis, emphasizing the potential impact of transient complexes on cellular pathways.

See also the graphical abstract(Fig. 1).