Biology subjects

Nyandwi, S. P.

Publications and source records attributed to Nyandwi, S. P..

3 recordsLinked to original sources

bioRxiv2026

A Metabolic Labeling Strategy for Tracking Protein Synthesis in Complex Biological Systems

Protein synthesis supports most biological processes. In the brain in particular, protein synthesis plays a critical role in physiological and pathological states. Here, we describe Tellurophene-Alkyne Cycloaddition-mediated Amino acid Tagging (TeACAT), a versatile strategy for fast, facile, and flexible tagging of newly synthesized proteins in mice. TeACAT is based on metabolic incorporation of the non-canonical amino acid TePhe into proteins by the endogenous protein synthesis machinery. Due to their high similarity, TePhe can efficiently replace canonical Phe without dietary or genetic manipulation. The subsequent bio-orthogonal reaction of TePhe with either fluorescent dyes or affinity handles enables both visualization and affinity enrichment of proteins synthesized during TePhe exposure. TeACAT is compatible with immunofluorescence for cell-type specific visualization of protein synthesis with subcellular resolution and can be used in conjunction with routine proteomics to identify and quantify newly synthesized proteins. Robust incorporation into the mouse proteome was observed on the scale of hours to days, allowing the interrogation of various biological processes. In summary, TeACAT enables the visualization and quantification of protein synthesis with minimal perturbation for biological discoveries.

molecular biology↗

bioRxiv2025

RARS1 integration into the multisynthetase complex is crucial for mammalian brain development

Aminoacyl tRNA synthetases occupy a central role in protein synthesis by charging tRNAs with their cognate amino acid. Eight aminoacyl-tRNA synthetases with nine enzymatic activities form a large protein complex but the breadth of functions mediated by the multisynthetase complex remains elusive. Neurological disorders have been associated with mutations within the domain tethering Arginyl-tRNA synthetase (RARS1) to the multisynthetase complex, which offers an interesting bridge between protein synthesis and neurodevelopment. To interrogate this connection, we developed a mouse model where RARS1 is excluded from the multisynthetase complex in the forebrain. We observed profound disruptions in neural development as attested by drastically reduced forebrain size and behavioral deficits. At the molecular level, neurodevelopmental and ribosomal genes were dysregulated. Finally, the subcellular localization of RARS1 and its colocalization with other translational machinery components were perturbed. Altogether, our results reveal the necessity of RARS1 integration in the multisynthetase complex for proper neurodevelopment.

molecular biology↗

bioRxiv2025

A disease-causing Isoleucyl-tRNA synthetase variant leads to altered protein complex formation and cellular stress response

Aminoacyl-tRNA synthetases are key enzymes in protein synthesis, as they catalyze the attachment of amino acids to their designated, cognate tRNAs. As such, mutations in aminoacyl-tRNA synthetases are associated with severe diseases, such as neurodevelopmental disorders. Many of these mutations occur in the catalytically active site or tRNA binding domains, however, others can affect domains associated with multisynthetase complex formation. Here, we investigate a disease-causing mutation in the UNE-L domain of Isoleucyl-tRNA synthetase (IARS1, IleRS), which mediates IleRS interactions within the multisynthetase complex. Interestingly, levels of the resulting protein were severely reduced in comparison to wildtype IleRS. While bulk protein synthesis and cell proliferation were not affected, the integrated stress response signaling pathway was altered. This change was exacerbated in low glucose medium, suggesting that mutant cells could respond differently to cellular stress. Our study hints at a possible underlying disease mechanism, where catalytic activity might not be affected but instead complex formation and protein stability.

molecular biology↗