A glucose-starvation response governs endocytic trafficking and eisosomal retention of surface cargoes in budding yeast

Abstract

Eukaryotic cells adapt their metabolism to the extracellular environment. Downregulation of surface cargo proteins in response to nutrient stress reduces the burden of anabolic processes whilst elevating catabolic production in the lysosome. We show that glucose starvation in yeast triggers a transcriptional response that increases internalisation from the plasma membrane. Nuclear export of the Mig1 transcriptional repressor in response to glucose starvation increases levels of the Yap1801 and Yap1802 clathrin adaptors, which is sufficient to increase cargo internalisation. Beyond this, we show that glucose starvation results in Mig1-independent transcriptional upregulation of various eisosomal factors. These factors serve to sequester a portion of nutrient transporters at existing eisosomes, through the presence of Ygr130c and biochemical and biophysical changes in Pil1, allowing cells to persist throughout the starvation period and maximise nutrient uptake upon return to replete conditions. This provides a physiological benefit for cells to rapidly recover from glucose starvation. Collectively, this remodelling of the surface protein landscape during glucose starvation calibrates metabolism to available nutrients.This article has an associated First Person interview with the first author of the paper.

The α‐arrestin family of ubiquitin ligase adaptors links metabolism with selective endocytosis

“…Interestingly, a fraction of nutrient transporters might be protected from starvation‐induced endocytosis because they laterally segregate into MCCs, which increase in number and size upon starvation. [Gournas et al., 2018; Laidlaw et al., 2020].…”

Investigating molecular crowding during cell division in budding yeast with FRET

“…Mid-log phase culture were diluted to OD 600 = ∼0.2 before being adhered to treated coverslips for 5 minutes at ambient temperature and then washed three times with imaging media to remove any unattached cells. Media exchanges were performed using microfluidics as previously described (Laidlaw et al, 2021).…”

“…Typically, the field of view is confined to the area encompassing just a few individual cells to allow rapid readout from the camera pixel array, allowing exploration of millisecond time scale cellular dynamics and accurate diffusion coefficient calculation (Plank et al, 2009; Wollman et al, 2016). Alongside this, tracking single molecules with Slimfield microscopy has been used to resolve oligomerization states of molecular assemblies in vivo (Badrinarayanan et al, 2012; Laidlaw et al, 2021; Shashkova et al, 2017, 2020; Sun et al, 2019; Syeda et al, 2019; Wollman et al, 2017). The crGE sensor copy numbers (i.e., number of sensor molecules present per cell) were also measured in previous work (Shepherd et al, 2020a), demonstrating that crowding readout in the cell was independent of local sensor concentration.…”

Recycling of cell surface membrane proteins from yeast endosomes is regulated by ubiquitinated Ist1

“…The plasma membrane (PM) hosts a variety of functionally diverse proteins that are regulated by intracellular trafficking pathways. Surface proteins can be downregulated through endocytosis and trafficking to the lysosome (vacuole in yeast), for example specific downregulation of receptors / transporters recognising ligand / substrate (Davis et al, 1993;Séron et al, 1999) or more general cargo endocytosis following stress (Laidlaw et al, 2020;Müller et al, 2015). (Laidlaw et al, 2020;MacGurn et al, 2011;Müller et al, 2015) Endocytosed surface cargoes that retain a ubiquitination signal are targeted through the multivesicular body (MVB) pathway, packaged into intraluminal vesicles (ILVs) and then delivered to the vacuole for degradation (Katzmann et al, 2001;Urbanowski and Piper, 2001).…”

“…Surface proteins can be downregulated through endocytosis and trafficking to the lysosome (vacuole in yeast), for example specific downregulation of receptors / transporters recognising ligand / substrate (Davis et al, 1993;Séron et al, 1999) or more general cargo endocytosis following stress (Laidlaw et al, 2020;Müller et al, 2015). (Laidlaw et al, 2020;MacGurn et al, 2011;Müller et al, 2015) Endocytosed surface cargoes that retain a ubiquitination signal are targeted through the multivesicular body (MVB) pathway, packaged into intraluminal vesicles (ILVs) and then delivered to the vacuole for degradation (Katzmann et al, 2001;Urbanowski and Piper, 2001). Ubiquitinated cargoes are recognised by the Endosomal Sorting Complex Required for Transport (ESCRT) complexes, with ESCRT-0 and ESCRT-I abundant in ubiquitin binding domains (Shields et al, 2009).…”