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Volume 67, Issue 1, Pages e5 (July 2017)

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1 Volume 67, Issue 1, Pages 84-95.e5 (July 2017)
Autophagy-Dependent Shuttling of TBC1D5 Controls Plasma Membrane Translocation of GLUT1 and Glucose Uptake  Srirupa Roy, Andrew M. Leidal, Jordan Ye, Sabrina M. Ronen, Jayanta Debnath  Molecular Cell  Volume 67, Issue 1, Pages e5 (July 2017) DOI: /j.molcel Copyright © 2017 Elsevier Inc. Terms and Conditions

2 Molecular Cell 2017 67, 84-95.e5DOI: (10.1016/j.molcel.2017.05.020)
Copyright © 2017 Elsevier Inc. Terms and Conditions

3 Figure 1 Autophagy Facilitates Glucose Uptake and Lactate Production in Hypoxic Cells by Promoting Cell Surface Expression of GLUT1 (A and B) MEFs of indicated genotypes were cultured in normoxia (N, 21% O2) or exposed to hypoxia (H, 1% O2) in 1-13C-glucose-containing media for 48 hr; extracellular 3-13C-lactate levels measured by NMR spectroscopy (mean ± SEM, n = 3 independent experiments). (C and D) MEFs exposed to H for 24 hr were labeled with 2-NBDG (100 μM) for 3 hr to measure glucose uptake (mean ± SEM, n = 3). (E) Cells exposed to H for the indicated times were lysed and immunoblotted for indicated proteins. (F) Relative mRNA expression of indicated transcripts in atg5+/+ and atg5−/− MEFs after exposure to H for 18 hr (mean ± SEM, n = 3). (G) Indicated cell types were exposed to H for 24 hr and immunostained for GLUT1 protein. Scale bars, 25 μm. (H and I) Cells transiently expressing Flag-GLUT1 were exposed to H for 24 hr; cell surface expression of Flag-GLUT1 was FACS quantified (mean ± SEM, n = 3). (J) 2-NBDG uptake in wild-type MEFs exposed to H in the presence of WZB117 (10 μM) for 24 hr (mean ± SEM, n = 4). p values calculated using ANOVA followed by Tukey’s HSD test. ∗∗∗p < 0.001, ∗∗p < 0.01, ∗p < 0.05; ns, not significant. Related to Figures S1 and S2. Molecular Cell  , e5DOI: ( /j.molcel ) Copyright © 2017 Elsevier Inc. Terms and Conditions

4 Figure 2 Autophagy Promotes GLUT1 Recycling to the Plasma Membrane
(A and B) Indicated cell types transiently expressing Flag-GLUT1 incubated with α-Flag, washed, and cultured at 37°C for indicated times prior to staining with Alexa 488 secondary antibody to determine the fraction of surface label remaining by flow cytometry (mean ± SEM, n = 3 independent experiments). (C and D) Cells transiently expressing Flag-GLUT1 incubated with α-Flag at 37°C in full media, washed, and chased in glucose-free media for indicated times, followed by staining with Alexa 488 secondary antibody to determine the kinetics of surface Flag-GLUT1 re-emergence by flow cytometry (mean ± SEM, n = 3). (E) Cells stained with Alexa Fluor 488-conjugated transferrin (Tfn) at 37°C in serum-free media, and chased in full media (mean ± SEM, n = 3). p values calculated using unpaired t test. ∗p < 0.05. (F) Confocal live-cell images of atg5+/+ and atg5−/− MEFs stably expressing GFP-GLUT1 after 2 hr of glucose starvation for the indicated times. Insets show magnification of the boxed regions. In top insets, arrows delineate GFP-GLUT1-containing vesicular structures migrating toward the plasma membrane in atg5+/+ MEFs. Scale bar, 10 μm. Related to Movies S1 and S2. Molecular Cell  , e5DOI: ( /j.molcel ) Copyright © 2017 Elsevier Inc. Terms and Conditions

5 Figure 3 Autophagy Deficiency Causes GLUT1 Mis-sorting to Late Endolysosomes (A) atg5+/+ and atg5−/− MEFs exposed to hypoxia (H, 1% O2) for 24 hr and immunostained for GLUT1 and LAMP1. (B) Pearson’s correlation coefficient for GLUT1-LAMP1 colocalization (mean ± SEM, n = 30 cells from 3 independent experiments). (C) Cells stably expressing GFP-GLUT1 exposed to H for 24 hr or subject to acute glucose starvation (-glc) for 18 hr and probed for GFP and LAMP1. (D) Pearson’s correlation coefficient for GFP-LAMP1 colocalization (mean ± SEM, n = 45 cells from 3 independent experiments). Cont, Control (full media, 20% O2); H, hypoxia (1% O2), -glc, glucose-deficient media. p values calculated using ANOVA followed by Tukey’s HSD test. ∗∗∗p < 0.001, ∗∗p < 0.01, ∗p < 0.05; ns, not significant. Scale bars 10 μm. Related to Figure S3. Molecular Cell  , e5DOI: ( /j.molcel ) Copyright © 2017 Elsevier Inc. Terms and Conditions

6 Figure 4 Autophagy-Mediated GLUT1 Trafficking Is Retromer Dependent
(A) atg5+/+ and atg5−/− MEFs stably expressing GFP-GLUT1 were exposed to hypoxia (H) for 24 hr or glucose starved (-glc) for 18 hr and immunoblotted for VPS35, VPS26, and VPS29. (B–D) atg5+/+ MEFs expressing GFP-GLUT1 were transfected with non-targeting control (CTL) or VPS35 siRNAs; 24 hr after transfection, cells were exposed to hypoxia (H) for 24 hr or glucose starved (-glc) for 18 hr. (B) Cells were lysed and immunoblotted with indicated antibodies. (C) MEFs immunostained for GFP and LAMP1. (D) Pearson’s correlation coefficient for GFP-LAMP1 colocalization. p values calculated using ANOVA followed by Tukey’s HSD test (mean ± SEM; n = 27 for CTL siRNA cells and n = 45 for VPS35 siRNA cells imaged over 3 independent experiments). (E and F) Cells were first transfected with siRNAs against non-targeting control (CTL) or VPS35 and subsequently with Flag-GLUT1 24 hr later. Kinetics of Flag-GLUT1 recycling over indicated times measured by flow cytometry (mean ± SEM, n = 3). (G) Cells were glucose starved for 18 hr and immunostained for VPS35. (H) The number of VPS35 puncta per cell were quantified (mean ± SEM; n = 60 cells per condition from 3 independent experiments). (I) Cells were exposed to hypoxia for 48 hr and immunostained for MCT1 and LAMP1. Scale bars represent 25 μM. p values calculated using ANOVA followed by Tukey’s HSD test. ∗∗∗p < 0.001, ∗p < Related to Figure S4. Molecular Cell  , e5DOI: ( /j.molcel ) Copyright © 2017 Elsevier Inc. Terms and Conditions

7 Figure 5 Autophagy-Dependent Shuttling of TBC1D5 from the Retromer to LC3+ Compartments Controls GLUT1 Trafficking (A) atg5−/− MEFs were transfected with siRNAs against non-targeting control (CTL) and TBC1D5 and glucose starved for 18 hr and lysates were immunoblotted for TBC1D5 and retromer subunits. (B) atg5−/− MEFs were first transfected with CTL or TBC1D5 siRNAs and subsequently transfected with Flag-GLUT1 24 hr later. Kinetics of Flag-GLUT1 recycling over indicated times measured by flow cytometry (mean ± SEM, n = 3). p values calculated using unpaired t test. (C) HEK293T cells were transiently transfected with Flag-TBC1D5, V5-VPS35, and Myc-LC3A. Cells were glucose starved for 8 hr. Lysates were immunoprecipitated with α-Flag (left) or α-Myc (right), resolved on SDS-PAGE, and immunoblotted as indicated. (D) HEK293T cells transiently overexpressing Myc-LC3A and Flag-TBC1D5 were glucose starved for 6 hr and immunostained with α-Flag and α-Myc. Scale bar, 10 μm. (E) HEK293T cells with or without ATG7 deletion were transiently transfected with Flag-TBC1D5 and V5-VPS35; cells were glucose starved and lysates were immunoprecipitated with α-Flag and immunoblotted as indicated. Right: Quantification of co-immunoprecipitated V5-VPS35 (mean ± SEM, n = 3 independent experiments). p values calculated using ANOVA followed by Tukey’s HSD test. (F) atg5−/− MEFs were transfected with CTL or TBC1D5 siRNAs, glucose starved for 18 hr, and immunostained for VPS35. Scale bar, 25 μm. (G) Quantification of the number of VPS35 puncta per cell (mean ± SEM; n = 60 cells from 3 independent experiments). p values calculated using unpaired t test. ∗∗∗p < 0.001, ∗p < 0.05; ns, not significant. Related to Figure S4. Molecular Cell  , e5DOI: ( /j.molcel ) Copyright © 2017 Elsevier Inc. Terms and Conditions


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