Vienna Biocenter

Ashwin and FAM98 paralogs define nuclear and cytoplasmic RNA ligase complexes for tRNA biogenesis

Abstract The tRNA ligase complex (tRNA-LC) seals tRNA exon halves in the nucleus during pre-tRNA splicing and XBP1 -mRNA exons in the cytoplasm as part of the unfolded protein response (UPR). This dual function requires the tRNA-LC to be either nuclear or cytoplasmic. Here, we re...

Structural framework for the assembly of the human tRNA ligase complex

Abstract In human cells, a subset of tRNA-encoding genes contain introns. These are removed by a spliceosome-independent pathway in which the tRNA splicing endonuclease complex catalyzes intron excision. The resulting exons are subsequently ligated by the tRNA-ligase complex (tRN...

Unified down-stream analysis of crosslinking mass spectrometry results with pyXLMS

Abstract Crosslinking mass spectrometry has become the method of choice for the identification of protein-protein interactions and for gaining insight into the structures of proteins in vivo. However, connecting crosslink search engine results with down-stream analysis tools, and...

Reconstitution of multistep recruitment of ULK1 to membranes in autophagy

Abstract The Human ULK1 autophagy-initiating complex consists of ULK1, FIP200, and the HORMA domain heterodimer ATG13:ATG101. PI3P is essential to recruit ULK1C to membranes for ULK1, but ULK1C subunits do not contain PI3P-binding domains. Here we show that the ATG13:ATG101 dimer...

Conformational asymmetry of replicated human chromosomes

Abstract DNA replication creates two sister chromatids that must acquire specific three-dimensional conformations to support genome function and stability. This organization is largely mediated by cohesin complexes, which extrude intra-chromosomal loops and link two chromatids, t...

A lipid transfer-dependent feedback loop activates ATG9A compartments in autophagy initiation

Abstract Autophagy degrades cellular material by sequestering it within autophagosomes, which form de novo from precursors called phagophores. Phagophore assembly and expansion require ATG9A-positive seed compartments, the lipid transfer protein ATG2A, and the class III phosphati...

Transposon end recognition and excision mechanisms of type I-F CRISPR-associated transposases

Abstract CRISPR-associated transposons (CASTs) are Tn7-like elements that have co-opted RNA-guided CRISPR effectors for targeted DNA insertion. CASTs have been adapted as genome editing tools for programmable, site-specific integration. Among them, the type I-F system from Ps e u...

VIA1 is a conserved regulator of thylakoid membrane integrity that acts through VIPP1

Abstract Thylakoid membranes are indispensable for oxygenic photosynthesis, yet the mechanisms that protect these membranes from photooxidative damage remain poorly understood. By screening previously uncharacterized proteins induced during the chloroplast unfolded protein respon...

Peripheral lysosomes recruit PLEKHG3 to focal adhesions and restrain protrusion dynamics

Lysosomes are dynamic organelles regulating metabolic signaling by recruiting cytosolic molecules to protein platforms on their limiting membrane. We used proximity labeling to define interactors and vicinal proteins of LAMTOR3, a component of the Ragulator scaffold that controls...