Fig. 4: Nutrient deprivation influences the rate of cargo egress from the ER. | Nature Communications

Fig. 4: Nutrient deprivation influences the rate of cargo egress from the ER.

From: Nutrient deprivation alters the rate of COPII subunit recruitment at ER subdomains to tune secretory protein transport

Fig. 4

a Control cells expressing ss-DsRed were maintained under nutrient replete conditions or subjected to acute (2 h) or long-term (24 h) nutrient deprivation prior to SLF-mediated cargo release and live cell confocal imaging. Representative images zoomed to the perinuclear region of cells are shown at various timepoints. Bar, 1 μm. b Confocal imaging of control cells expressing ss-DsRed under various conditions (nutrient replete, green; 2 h nutrient depletion, magenta; 24 h nutrient depletion, blue) was used to monitor its synchronous release from the ER. Based on fluorescence intensity, the percentage of ss-DsRed present within the perinuclear region relative to its maximal accumulation there was quantified over time and fit to an exponential plateau (discontinued upon reaching maximal intensity). Error, as displayed by lightly colored bands around fitted exponential plateau trend lines, represents mean +/- SEM (n = 20 cells each; 3 biological replicates each). Half-times to perinuclear accumulation of ss-DsRed were calculated based on the plots (see Source Data file). c Cells natively expressing SNAP-tag-ERGIC-53 were maintained under nutrient replete conditions or subjected to nutrient depletion and visualized using HILO imaging. Representative images zoomed to newly forming sites (highlighted by arrowheads) are shown at various timepoints (n = 20 cells each; 3 biological replicates each). Bar, 1 μm. d The intensities of new sites harboring SNAP-tag-ERGIC-53 were tracked under various nutrient availability conditions (nutrient replete, green; 2 hour nutrient depletion, magenta; 24 h nutrient depletion, blue). Error, as highlighted by lightly colored bands around smoothed trend lines, represents mean +/- SEM (>6000 tracked particles, each condition). Solid gray (p < 0.05) and checkered gray (p < 0.1) regions represent significant differences, calculated using multiple, unpaired t tests at each time point. Specific p values are provided in the Source Data file.

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