DOI: 10.1101/487702Dec 6, 2018Paper

Membrane potential regulates the dynamic localisation of mammalian proteasomes

BioRxiv : the Preprint Server for Biology
Yu ZhangYu Ye


Proteasomes are molecular machineries responsible for regulated protein degradation and general homeostasis. The distribution of this degradation capacity is reflected by the cellular localisation of proteasomal particles. Here we combine super-resolution imaging, single-particle tracking (SPT) and single-cell patch clamp techniques to investigate the localisation and translocation of endogenous mammalian proteasomes tagged with fluorescent proteins. While proteasomes are found dispersed in the cell without distinct localisation, we detect a higher density of proteasomes in the nucleus compared to the ER and the cytosol. SPT of proteasomes revealed two populations with diffusion coefficients averaging ~4 and ~0.8 μm2/s. The ratio between these two populations could be altered upon changed cellular conditions. We further report that proteasomal particles translocate to the cell periphery during hyperpolarisation, while depolarisation re-localises proteasomes to the cell interior. Depolymerising microtubules or actin filaments inhibited this potential-dependent translocation. Our results suggest that at resting membrane potential proteasomes undergo diffusion-based motions, while membrane polarisation may induce cytoskeleton-depe...Continue Reading

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