Biology subjects

Schneider-Poetsch, T.

Publications and source records attributed to Schneider-Poetsch, T..

3 recordsLinked to original sources

bioRxiv2023

Chemical genetic interaction linking eIF5A hypusination and mitochondrial integrity

The eukaryotic translation factor eIF5A plays an important role in translation elongation, especially across stretches of prolines and charged amino acids, and in translation termination. eIF5A undergoes hypusination, a post-translational modification unique to this protein, although the role of hypusination in the function of eIF5A remains elusive. Here, we investigated the cellular defects induced by the hypusination inhibitor GC7 (N1-guanyl-1,7-diaminoheptane). Proteome, translatome, and transcriptome analyses indicated that GC7 downregulated a subset of mitochondrial proteins and DNA, causing mitochondrial stress and eliciting the integrated stress response. Chemical genomic screening using barcoded shRNA libraries identified genes encoding proteins involved in polyamine metabolism/transport and MPV17L2, a mitochondrial disease gene homologue whose product regulates mitochondrial translation. Depletion of MPV17L2 caused hypersensitivity to GC7 and phenocopied the effects of GC7 treatment. These results suggest that eIF5A hypusination and MPV17L2 synthetically regulate mitochondrial molecular synthesis and integrity.

cell biology↗

bioRxiv2023

Pateamine A mediates RNA sequence-selective translation repression by anchoring eIF4A and DDX3 to GNG motifs

Small-molecule compounds that elicit mRNA-selective translation repression have attracted interest due to their potential for expansion of druggable space. However, only limited examples have been reported to date. Here, we show that pateamine A (PatA) represses translation in an mRNA-selective manner by clamping eIF4A, a DEAD-box RNA-binding protein, on GNG motifs. Through a systematic comparison of multiple eIF4A inhibitors by ribosome profiling, we found that PatA has unique mRNA selectivity in translation repression. Unbiased Bind-n-Seq revealed that PatA-targeted eIF4A exhibits a sequence preference for GNG motifs in an ATP-independent manner. This unusual RNA binding sterically hinders scanning by 40S ribosomes. In silico simulation, combination of classical molecular dynamics simulation and quantum chemical calculation, and the subsequent development of an inactive PatA derivative revealed that the positive charge of the tertiary amine on the trienyl arm induces G selectivity. Moreover, we identified DDX3, another DEAD-box protein, as an alternative target of PatA, showing the same effect as on eIF4A. Our results provide an example of the sequence-selective anchoring of RNA-binding proteins and mRNA-selective inhibition of protein synthesis by small-molecule compounds.

molecular biology↗

bioRxiv2020

Splicing modulators elicit global translational repression by condensate-prone proteins translated from introns

Chemical splicing modulators that bind to the spliceosome have provided an attractive venue for cancer treatment. Splicing modulators induce accumulation and subsequent translation of a subset of intron-retained mRNAs. Yet, the biological effect of proteins containing translated intron sequences remains unclear. Here we identified a number of truncated proteins generated upon treatment with the splicing modulator spliceostatin A (SSA) using genome-wide ribosome profiling and bio-orthogonal non-canonical amino-acid tagging (BONCAT) mass spectrometry. A subset of these truncated proteins has intrinsically disordered regions, forms insoluble cellular condensates, and triggers the proteotoxic stress response through JNK phosphorylation, thereby inhibiting the mTORC1 pathway. In turn, this reduces global translation. These findings indicate that creating an overburden of condensate-prone proteins derived from introns represses translation and prevents further production of harmful truncated proteins. This mechanism appears to contribute to the antiproliferative and proapoptotic activity of splicing modulators.

molecular biology↗