Transcription Factor EB (TFEB) controls lysosomal biogenesis and autophagy in response to nutritional status and other stress factors. Although its regulation by nuclear translocation is known to involve a complex network of well-studied regulatory processes, the precise contribution of each of these mechanisms is unclear. Using microfluidics technology and real-time imaging coupled with mathematical modelling, we explored the dynamic regulation of TFEB under different conditions. We found that TFEB nuclear translocation upon nutrient deprivation happens in two phases: a fast one characterised by a transient boost in TFEB dephosphorylation dependent on transient calcium release mediated by mucolipin 1 (MCOLN1) followed by activation of the Calcineurin phosphatase, and a slower one driven by inhibition of mTORC1-dependent phosphorylation of TFEB. Upon refeeding, TFEB cytoplasmic relocalisation kinetics are determined by Exportin 1 (XPO1). Collectively, our results show how different mechanisms interact to regulate TFEB activation and the power of microfluidics and quantitative modelling to elucidate complex biological mechanisms.
© 2025. The Author(s).