Little is known about how mammalian cells maintain cell size homeostasis. We conducted a novel genetic screen to identify cell-size-controlling genes and isolated Largen, the product of a gene (PRR16) that increased cell size upon overexpression in human cells. In vitro evidence indicated that Largen preferentially stimulates the translation of specific subsets of mRNAs, including those encoding proteins affecting mitochondrial functions. The involvement of Largen in mitochondrial respiration was consistent with the increased mitochondrial mass and greater ATP production in Largen-overexpressing cells. Furthermore, Largen overexpression led to increased cell size in vivo, as revealed by analyses of conditional Largen transgenic mice. Our results establish Largen as an important link between mRNA translation, mitochondrial functions, and the control of mammalian cell size.

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Crowdsource volunteering efforts have contributed significantly to pandemic response and recovery during the COVID-19 outbreak. In such efforts, individual volunteers can collaborate to achieve rapid mobilisation toward emergent community demands. In this study, we quantitively study this phenomenon using the concept of self-organisation, by proposing a data-driven framework to investigate when and how self-organisation emerged during the pandemic response and how it relates to effectiveness of volunteer organisations in general. Using activity data collected from a mobile volunteer platform in Shenzhen, China, we found that volunteers’ task participation and social and task preferences show multiple phases of self-organisation in response to changing epidemic situations and centralised interventions. Simulation experiments further show that the self-organised volunteer system can become more responsive and more robust in the face of uncertain community demands with minimal centralised guidance.