Growing cells adopt common basic strategies to achieve optimal resource allocation under limited resource availability. Our current understanding of such “growth laws” neglects degradation, assuming that it occurs slowly compared to the cell cycle duration. Here we argue that this assumption cannot hold at slow growth, leading to important consequences. We propose a simple framework showing that at slow growth protein degradation is balanced by a fraction of “maintenance” ribosomes. Consequently, active ribosomes do not drop to zero at vanishing growth, but as growth rate diminishes, an increasing fraction of active ribosomes performs maintenance. Through a detailed analysis of compiled data, we show that the predictions of this model agree with data from E. coli and S. cerevisiae. Intriguingly, we also find that protein degradation increases at slow growth, which we interpret as a consequence of active waste management and/or recycling. Our results highlight protein turnover as an underrated factor for our understanding of growth laws across kingdoms.

Protein degradation sets the fraction of active ribosomes at vanishing growth / L. Calabrese, J. Grilli, M. Osella, C.P. Kempes, M. Cosentino Lagomarsino, L. Ciandrini. - In: PLOS COMPUTATIONAL BIOLOGY. - ISSN 1553-734X. - 18:5(2022), pp. e1010059.1-e1010059.23. [10.1371/journal.pcbi.1010059]

Protein degradation sets the fraction of active ribosomes at vanishing growth

M. Cosentino Lagomarsino
;
2022

Abstract

Growing cells adopt common basic strategies to achieve optimal resource allocation under limited resource availability. Our current understanding of such “growth laws” neglects degradation, assuming that it occurs slowly compared to the cell cycle duration. Here we argue that this assumption cannot hold at slow growth, leading to important consequences. We propose a simple framework showing that at slow growth protein degradation is balanced by a fraction of “maintenance” ribosomes. Consequently, active ribosomes do not drop to zero at vanishing growth, but as growth rate diminishes, an increasing fraction of active ribosomes performs maintenance. Through a detailed analysis of compiled data, we show that the predictions of this model agree with data from E. coli and S. cerevisiae. Intriguingly, we also find that protein degradation increases at slow growth, which we interpret as a consequence of active waste management and/or recycling. Our results highlight protein turnover as an underrated factor for our understanding of growth laws across kingdoms.
Protein Biosynthesis; Proteolysis; Ribosomes; Escherichia coli; Saccharomyces cerevisiae
Settore FIS/02 - Fisica Teorica, Modelli e Metodi Matematici
Settore BIO/09 - Fisiologia
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/946327
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