Biology subjects

Tippmann, F.

Publications and source records attributed to Tippmann, F..

3 recordsLinked to original sources

bioRxiv2025

Translation-driven temporal control for intertwined protein assembly

Protein complexes are essential to cells. However, how structurally intertwined protein subunits can assemble faithfully is poorly understood. Here, we reveal a "temporal control" mechanism driven by coupled ribosomes to form intertwined dimers. Using Disome Selective Profiling and optical tweezers, we show that the BTB domains of KEAP1, KLHL12, and PATZ1 form stable closed states as monomers, thus impeding proposed domain-swapping assembly routes. By contrast, the timed emergence of nascent chain segments during translation enables alternative folding-assembly pathways that bypass the closed monomeric state. Analysis indicates that this mechanism works in concert with dimerization quality control by the E3 ligase SCF-FBXL17, and is relevant across the BTB domain family. This study shows that ribosome cooperation expands the range of possible protein architectures.

molecular biology↗

bioRxiv2025

NAC promotes co-translational folding at the ribosomal tunnel exit

The nascent polypeptide-associated complex (NAC) coordinates enzymatic modifications and membrane targeting of nascent chains during translation. While NACs function as a dynamic hub for other factors is well-established, its direct role in co-translational folding is unclear. By proteome-wide profiling NAC co-translational interactions in human cells, we found that NAC recognizes emerging segments enriched in hydrophobicity and -helical propensity, within folded domains of cytonuclear proteins. Single-molecule and structural analyses reveal that NAC, via its {beta}-barrel domain, dynamically interacts with nascent chains at the ribosomal tunnel exit and is capable of promoting on-pathway folding. Compartment-specific nascent chain interactions of NAC further elucidate its role in targeting to the endoplasmic reticulum and mitochondrial membrane protein biogenesis. Together, these findings show that NAC acts as a bona fide co-translational chaperone that facilitates early protein folding at the ribosomal tunnel exit, expanding its functional repertoire in protein biogenesis.

biochemistry↗

bioRxiv2025

A simple, fast and cost-efficient protocol for ultra-sensitive ribosome profiling

Ribosome profiling has become an essential tool for studying mRNA translation in cells with codon-level resolution. However, its widespread application remains hindered by the labour-intensive workflow, low efficiency and high costs associated with sequencing sample preparation. Here, we present a new cost-effective and ultra-sensitive library preparation method that significantly advances the applicability of ribosome profiling. By implementing bead-coupled enzymatic reactions and product purifications, our approach increases both yield and throughput while maintaining high reproducibility. Demonstrating the sensitivity of the protocol we prepared libraries from as little as 12 fmol of RNA, which expands the feasibility of ribosome profiling from minimal input samples, such as derived from small populations, stressed cells, or patient-derived specimens. Additionally, we validate the versatility of the protocol across multiple species and demonstrate its applicability for RNA-seq library preparation. Altogether, this protocol provides a highly accessible and efficient alternative to existing ribosome profiling workflows, facilitating research in previously challenging experimental contexts.

systems biology↗