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bioRxiv · 10.1101/2024.04.22.590536

Stm1 regulates Ifh1 activity revealing crosstalk between ribosome biogenesis and ribosome dormancy

Bianco, E.·Bonassera, M.·Uliana, F.·Tilma, J.·Winkler, M.·Zencir, S.·Albert, B.·Oborska-Oplova, M.·Dechant, R.·Hugener, J.·Panse, V. G.·Pilhofer, M.·Kimmig, P.·Peter, M.
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Abstract

Ribosome abundance in changing environments is governed by biogenesis and degradation, but the underlying mechanisms regulating these opposing processes remain unknown. Here we show that Suppressor of Tom1 (Stm1), a dormancy factor protecting cytosolic ribosomes during starvation, has an unexpected function to promote ribosome biogenesis during exponential growth conditions. Indeed, Stm1 transiently localizes to the nucleolus and engages with pre-ribosomal particles. Stm1 upregulates transcription of ribosomal protein genes by directly binding the activation domain (AD) of the transcription factor Ifh1. These novel Stm1 functions confer rapamycin-sensitivity and are mediated by its C-terminal intrinsically disordered region (IDR), which is dispensable for ribosome hibernation. We conclude that Stm1 regulates ribosome homeostasis linking ribosome biogenesis and ribosome dormancy.

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Bianco, E., Bonassera, M., Uliana, F., Tilma, J., Winkler, M., Zencir, S., Albert, B., Oborska-Oplova, M., Dechant, R., Hugener, J., Panse, V. G., Pilhofer, M., Kimmig, P., Peter, M.. 2024-04-26. Stm1 regulates Ifh1 activity revealing crosstalk between ribosome biogenesis and ribosome dormancy. https://doi.org/10.1101/2024.04.22.590536

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