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Snieckute, G.

Publications and source records attributed to Snieckute, G..

4 recordsLinked to original sources

Resolution of collided ribosomes by ZNF598 is required for adipocyte energy dissipation

Cellular adaptation to stress evoked by high energy demand requires tight coordination between transcriptional programs, protein synthesis, and organelle function. In many physiological contexts, metabolic remodeling depends on increased mitochondrial capacity and activity, placing high demands on the translational machinery. Beige and brown adipocytes, which undergo rapid mitochondrial expansion and activation in response to physiological cues, provide a powerful model to study how cells adapt their translational output to meet increased metabolic demand. How translational fidelity is maintained, and stress-associated conflicts in protein synthesis are resolved during such adaptive processes, remains incompletely understood. Here, we identify ZNF598 as a key factor that resolves translation stress caused by ribosome collisions during metabolic adaptation of adipocytes. We show that diverse physiological stimuli, including hormonal signaling, environmental challenges, and dietary changes, induce ZNF598 and associated enzymes in metabolically active cells. ZNF598 is required for efficient mitochondrial biogenesis and function, supporting adaptive increases in respiration and energy expenditure. Loss of ZNF598 compromises these adaptive responses and leads to metabolic dysfunction, whereas enhancement of ZNF598 activity improves cellular and organismal metabolic flexibility. Together, these findings indicate that distal steps of the translational machinery are a rate-limiting factor for adaptation to increased energy demand.

cell biology↗

Initiation of a ZAKa-dependent Ribotoxic Stress Response by the Innate Immunity Endoribonuclease RNase L

RNase L is a regulated endoribonuclease in higher vertebrates that functions in antiviral innate immunity. Interferons induce OAS enzymes that sense double-stranded RNA of viral origin leading to synthesis of 2,5-oligoadenylate (2-5A) activators of RNase L. However, it is unknown precisely how RNase L inhibits viral infections. To isolate effects of RNase L from other effects of double-stranded RNA or virus, 2-5A was directly introduced into cells. Here we report that RNase L activation by 2-5A causes a ribotoxic stress response that requires the ribosome-associated MAP3K, ZAK. Subsequently, the stress-activated protein kinases (SAPK) JNK and p38 are phosphorylated. RNase L activation profoundly altered the transcriptome by widespread depletion of mRNAs associated with different cellular functions, but also by SAPK-dependent induction of inflammatory genes. Our findings show that 2-5A is a ribotoxic stressor that causes RNA damage through RNase L triggering a ZAK kinase cascade leading to proinflammatory signaling and apoptosis. HighlightsO_LIRNase L signals antiviral innate immunity from the ribosome C_LIO_LIThe ribotoxic stress response requires the MAP3K ZAK C_LIO_LIRNA cleavage leads to transcription of proinflammatory genes C_LIO_LIZAK contributes to apoptosis downstream of RNase L activity C_LI

immunology↗

Atypical TGF-beta Signaling Controls Neuronal Guidance in Caenorhabditis elegans

Coordinated expression of cell adhesion and signaling molecules is crucial for brain development. Here, we report that the Caenorhabditis elegans transforming growth factor-beta (TGF-{beta}) type I receptor SMA-6 (small-6) acts independently of its cognate TGF-{beta} type II receptor DAF-4 (dauer formation-defective-4) to control neuronal guidance. SMA-6 directs neuronal development from the epidermis through interactions with three, orphan, TGF-{beta} ligands. Intracellular signaling downstream of SMA-6 limits expression of NLR-1, an essential Neurexin-like cell adhesion receptor, to enable neuronal guidance. Together, our data identify an atypical TGF-{beta}-mediated regulatory mechanism to ensure correct development of the nervous system.

developmental biology↗

Alternative translation initiation generates a functionally distinct isoform of the stress-activated kinase MK2

Shaping of the proteome by alternative translation is an important mechanism of post-transcriptional gene regulation. It can lead to the expression of multiple protein isoforms originating from the same mRNA. Here we show that a novel, abundant and long isoform of the stress/p38MAPK-activated kinase MK2, a key regulator of transcription, migration, death signaling and post-transcriptional gene regulation, is constitutively translated from an alternative CUG translation initiation start site located in the 5'UTR of its mRNA. GC-rich sequences and putative G-quadruplex structures influence the usage of that codon as a translation initiation start site and the RNA helicase eIF4A1 is needed to ensure alternative isoform translation. We recapitulated the usage of the alternative start codon and determined the molecular properties of the short and a long MK2 isoforms. Phenotypically, only the short isoform phosphorylated Hsp27, supported migration and stress-induced immediate early gene (IEG) expression. Interaction profiling by quantitative mass-spectrometry revealed short isoform-specific binding partners that were associated with migration. In contrast, the long isoform contains additional putative phosphorylation sites in its unique N-terminus. In sum, our data reveal a longer and previously non-described isoform of MK2 with distinct physiological properties originating from alternative translation.

molecular biology↗