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Phosphoinositide kinase signaling controls ER-PM cross-talk.

Omnus DJ, Manford AG, Bader JM, Emr SD, Stefan CJ - Mol. Biol. Cell (2016)

Bottom Line: However, little is known about the sensory mechanisms for detecting membrane composition and how lipid metabolism is regulated in response to membrane stress.We find that phosphoinositide (PI) kinase signaling controls a conserved PDK-TORC2-Akt signaling cascade as part of a homeostasis network that allows the endoplasmic reticulum (ER) to modulate essential responses, including Ca(2+)-regulated lipid biogenesis, upon plasma membrane (PM) stress.Furthermore, loss of ER-PM junctions impairs this protective response, leading to PM integrity defects upon heat stress.

View Article: PubMed Central - PubMed

Affiliation: MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, United Kingdom.

No MeSH data available.


Related in: MedlinePlus

Heat-induced membrane stress and PI metabolism regulate Pkh1 localization. (A) Pkh1 assembles into cortical patches upon heat shock. Wild-type cells expressing GFP-Pkh1 were grown at 26°C (top) and shifted to 42°C for 10 min (bottom). Arrows show examples of small GFP-Pkh1 cortical patches in wild-type cells at 26°C. The majority of GFP-Pkh1 foci are cortical, but internal patches are also observed. Scale bar, 5 μm. See Supplemental Figure S4C. (B) High-content quantitative analysis of GFP-Pkh1 distribution. Maxima for GFP-Pkh1 foci in single focal planes (1482 foci in total from 720 cells at 26 and 3742 foci in total from 1095 cells after heat shock at 42°C) were identified using Fiji. Results show the mean and SD from three independent experiments. (C) PI4P metabolism controls Pkh1 localization. GFP-Pkh1 localization in wild-type, sac1Δ, and Δtether cells. Arrows show examples of small GFP-Pkh1 cortical patches in wild-type cells at 26°C. GFP-Pkh1 puncta are increased in sac1Δ and Δtether cells at 26°C. Scale bar, 5 μm. (D) GFP-Pkh1 puncta are increased in sac1Δ and Δtether cells. Maxima for GFP-Pkh1 foci in single focal planes (1482 in total from 720 wild-type cells, 7258 in total from 1802 sac1Δ cells, and 3921 in total from 1261 Δtether cells at 26°C) were identified using Fiji. Results show the mean and SD from three independent experiments. See Supplemental Figure S4, D–F.
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Figure 4: Heat-induced membrane stress and PI metabolism regulate Pkh1 localization. (A) Pkh1 assembles into cortical patches upon heat shock. Wild-type cells expressing GFP-Pkh1 were grown at 26°C (top) and shifted to 42°C for 10 min (bottom). Arrows show examples of small GFP-Pkh1 cortical patches in wild-type cells at 26°C. The majority of GFP-Pkh1 foci are cortical, but internal patches are also observed. Scale bar, 5 μm. See Supplemental Figure S4C. (B) High-content quantitative analysis of GFP-Pkh1 distribution. Maxima for GFP-Pkh1 foci in single focal planes (1482 foci in total from 720 cells at 26 and 3742 foci in total from 1095 cells after heat shock at 42°C) were identified using Fiji. Results show the mean and SD from three independent experiments. (C) PI4P metabolism controls Pkh1 localization. GFP-Pkh1 localization in wild-type, sac1Δ, and Δtether cells. Arrows show examples of small GFP-Pkh1 cortical patches in wild-type cells at 26°C. GFP-Pkh1 puncta are increased in sac1Δ and Δtether cells at 26°C. Scale bar, 5 μm. (D) GFP-Pkh1 puncta are increased in sac1Δ and Δtether cells. Maxima for GFP-Pkh1 foci in single focal planes (1482 in total from 720 wild-type cells, 7258 in total from 1802 sac1Δ cells, and 3921 in total from 1261 Δtether cells at 26°C) were identified using Fiji. Results show the mean and SD from three independent experiments. See Supplemental Figure S4, D–F.

Mentions: Next we examined Pkh1 subcellular localization under normal and heat shock conditions using a functional GFP-Pkh1 fusion expressed from its own promoter (Figure 4 and Supplemental Figure S4, A and B). In wild-type cells at 26°C, GFP-Pkh1 was mainly diffuse throughout the cytoplasm (Figure 4, A and C, and Supplemental Figure S4, C and F), but small, cortical puncta (one to three per cell) could be observed in cells (Figure 4, A and C arrows). On heat shock at 42°C, there was a measurable increase in the number of cortical GFP-Pkh1 foci per cell (Figure 4, A and B, and Supplemental Figure S4, C and F), as well as of puncta size and intensity. The enlarged GFP-Pkh1 foci at 42°C appeared to be mainly cortical, although intracellular puncta were also observed (Figure 4 and Supplemental Figure S4).


Phosphoinositide kinase signaling controls ER-PM cross-talk.

Omnus DJ, Manford AG, Bader JM, Emr SD, Stefan CJ - Mol. Biol. Cell (2016)

Heat-induced membrane stress and PI metabolism regulate Pkh1 localization. (A) Pkh1 assembles into cortical patches upon heat shock. Wild-type cells expressing GFP-Pkh1 were grown at 26°C (top) and shifted to 42°C for 10 min (bottom). Arrows show examples of small GFP-Pkh1 cortical patches in wild-type cells at 26°C. The majority of GFP-Pkh1 foci are cortical, but internal patches are also observed. Scale bar, 5 μm. See Supplemental Figure S4C. (B) High-content quantitative analysis of GFP-Pkh1 distribution. Maxima for GFP-Pkh1 foci in single focal planes (1482 foci in total from 720 cells at 26 and 3742 foci in total from 1095 cells after heat shock at 42°C) were identified using Fiji. Results show the mean and SD from three independent experiments. (C) PI4P metabolism controls Pkh1 localization. GFP-Pkh1 localization in wild-type, sac1Δ, and Δtether cells. Arrows show examples of small GFP-Pkh1 cortical patches in wild-type cells at 26°C. GFP-Pkh1 puncta are increased in sac1Δ and Δtether cells at 26°C. Scale bar, 5 μm. (D) GFP-Pkh1 puncta are increased in sac1Δ and Δtether cells. Maxima for GFP-Pkh1 foci in single focal planes (1482 in total from 720 wild-type cells, 7258 in total from 1802 sac1Δ cells, and 3921 in total from 1261 Δtether cells at 26°C) were identified using Fiji. Results show the mean and SD from three independent experiments. See Supplemental Figure S4, D–F.
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Figure 4: Heat-induced membrane stress and PI metabolism regulate Pkh1 localization. (A) Pkh1 assembles into cortical patches upon heat shock. Wild-type cells expressing GFP-Pkh1 were grown at 26°C (top) and shifted to 42°C for 10 min (bottom). Arrows show examples of small GFP-Pkh1 cortical patches in wild-type cells at 26°C. The majority of GFP-Pkh1 foci are cortical, but internal patches are also observed. Scale bar, 5 μm. See Supplemental Figure S4C. (B) High-content quantitative analysis of GFP-Pkh1 distribution. Maxima for GFP-Pkh1 foci in single focal planes (1482 foci in total from 720 cells at 26 and 3742 foci in total from 1095 cells after heat shock at 42°C) were identified using Fiji. Results show the mean and SD from three independent experiments. (C) PI4P metabolism controls Pkh1 localization. GFP-Pkh1 localization in wild-type, sac1Δ, and Δtether cells. Arrows show examples of small GFP-Pkh1 cortical patches in wild-type cells at 26°C. GFP-Pkh1 puncta are increased in sac1Δ and Δtether cells at 26°C. Scale bar, 5 μm. (D) GFP-Pkh1 puncta are increased in sac1Δ and Δtether cells. Maxima for GFP-Pkh1 foci in single focal planes (1482 in total from 720 wild-type cells, 7258 in total from 1802 sac1Δ cells, and 3921 in total from 1261 Δtether cells at 26°C) were identified using Fiji. Results show the mean and SD from three independent experiments. See Supplemental Figure S4, D–F.
Mentions: Next we examined Pkh1 subcellular localization under normal and heat shock conditions using a functional GFP-Pkh1 fusion expressed from its own promoter (Figure 4 and Supplemental Figure S4, A and B). In wild-type cells at 26°C, GFP-Pkh1 was mainly diffuse throughout the cytoplasm (Figure 4, A and C, and Supplemental Figure S4, C and F), but small, cortical puncta (one to three per cell) could be observed in cells (Figure 4, A and C arrows). On heat shock at 42°C, there was a measurable increase in the number of cortical GFP-Pkh1 foci per cell (Figure 4, A and B, and Supplemental Figure S4, C and F), as well as of puncta size and intensity. The enlarged GFP-Pkh1 foci at 42°C appeared to be mainly cortical, although intracellular puncta were also observed (Figure 4 and Supplemental Figure S4).

Bottom Line: However, little is known about the sensory mechanisms for detecting membrane composition and how lipid metabolism is regulated in response to membrane stress.We find that phosphoinositide (PI) kinase signaling controls a conserved PDK-TORC2-Akt signaling cascade as part of a homeostasis network that allows the endoplasmic reticulum (ER) to modulate essential responses, including Ca(2+)-regulated lipid biogenesis, upon plasma membrane (PM) stress.Furthermore, loss of ER-PM junctions impairs this protective response, leading to PM integrity defects upon heat stress.

View Article: PubMed Central - PubMed

Affiliation: MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, United Kingdom.

No MeSH data available.


Related in: MedlinePlus