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Spontaneous and electric field-controlled front-rear polarization of human keratinocytes.

Saltukoglu D, Grünewald J, Strohmeyer N, Bensch R, Ulbrich MH, Ronneberger O, Simons M - Mol. Biol. Cell (2015)

Bottom Line: By contrast, we found a crucial role for extracellular pH as well as G protein coupled-receptor (GPCR) or purinergic signaling in the control of directionality.Overall our work puts forward a model in which the EF uses distinct polarization pathways.The cathodal pathway involves GPCR/purinergic signaling and is dominant over the anodal pathway at neutral pH.

View Article: PubMed Central - PubMed

Affiliation: Center for Systems Biology, University of Freiburg, 79104 Freiburg, Germany Renal Division, University Hospital Freiburg, 79106 Freiburg, Germany Spemann Graduate School of Biology and Medicine, University of Freiburg, 79104 Freiburg, Germany BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.

No MeSH data available.


Interplay of membrane signaling with pHe in the EF response. (A–D) Rose plots representing the direction of symmetry breaking with indicated inhibitors and doses at the indicated pHe values. (A) Suramin treatment leads to anodal polarization at pHe 6.6, 7.4, and 7.8. At pHe 8.0, cathodal polarization is restored. (B) Cathodal polarization is also restored for Gallein treatment at pHe 8.0. (C) Gαi inhibition with PTX shows anodal bias at low pH (pHe 6.6) and cathodal bias at high pH (pHe 8.0). (D) Cathodal polarization in PPADS-treated cells at high pHe. (E) Untreated cells show randomization at pHe 7.0 and strong cathodal polarization at pHe 8.0. (F) Graph showing percentage of cathodal polarization at different pHe values. Different symbols represent different treatments.
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Figure 6: Interplay of membrane signaling with pHe in the EF response. (A–D) Rose plots representing the direction of symmetry breaking with indicated inhibitors and doses at the indicated pHe values. (A) Suramin treatment leads to anodal polarization at pHe 6.6, 7.4, and 7.8. At pHe 8.0, cathodal polarization is restored. (B) Cathodal polarization is also restored for Gallein treatment at pHe 8.0. (C) Gαi inhibition with PTX shows anodal bias at low pH (pHe 6.6) and cathodal bias at high pH (pHe 8.0). (D) Cathodal polarization in PPADS-treated cells at high pHe. (E) Untreated cells show randomization at pHe 7.0 and strong cathodal polarization at pHe 8.0. (F) Graph showing percentage of cathodal polarization at different pHe values. Different symbols represent different treatments.

Mentions: Finally, we tested different pH conditions for the pharmacological treatments affecting directionality. We focused on the inhibitions of GPCR and purinergic signaling. For the treatments that cause ­reversal at normal pHe (suramin and gallein), we observed anodal polarization at pHe 6.6, 7.0, and 7.8, with restoration of cathodal polarization at pHe 8.0 (Figure 6, A, B, and F). This suggests that the threshold for cathodal polarization can be pushed toward alkaline pHe values when GPCR and purinergic signaling is inhibited. For the treatments that cause randomization at neutral pHe (PTX and PPDS), we found anodal polarization at low pHe and cathodal polarization at high pHe (Figure 6, C, D, and F). Considering that randomization could be an intermediate step when switching from anodal to cathodal polarization, we predicted that a mildly acidic pHe would cause randomization in untreated cells. This was indeed the case: randomization was found for untreated cells at pHe 7.0. At pHe 8.0, on the other hand, cathodal polarization was 10% more efficient than at normal pHe (Figure 6, E and F).


Spontaneous and electric field-controlled front-rear polarization of human keratinocytes.

Saltukoglu D, Grünewald J, Strohmeyer N, Bensch R, Ulbrich MH, Ronneberger O, Simons M - Mol. Biol. Cell (2015)

Interplay of membrane signaling with pHe in the EF response. (A–D) Rose plots representing the direction of symmetry breaking with indicated inhibitors and doses at the indicated pHe values. (A) Suramin treatment leads to anodal polarization at pHe 6.6, 7.4, and 7.8. At pHe 8.0, cathodal polarization is restored. (B) Cathodal polarization is also restored for Gallein treatment at pHe 8.0. (C) Gαi inhibition with PTX shows anodal bias at low pH (pHe 6.6) and cathodal bias at high pH (pHe 8.0). (D) Cathodal polarization in PPADS-treated cells at high pHe. (E) Untreated cells show randomization at pHe 7.0 and strong cathodal polarization at pHe 8.0. (F) Graph showing percentage of cathodal polarization at different pHe values. Different symbols represent different treatments.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

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Figure 6: Interplay of membrane signaling with pHe in the EF response. (A–D) Rose plots representing the direction of symmetry breaking with indicated inhibitors and doses at the indicated pHe values. (A) Suramin treatment leads to anodal polarization at pHe 6.6, 7.4, and 7.8. At pHe 8.0, cathodal polarization is restored. (B) Cathodal polarization is also restored for Gallein treatment at pHe 8.0. (C) Gαi inhibition with PTX shows anodal bias at low pH (pHe 6.6) and cathodal bias at high pH (pHe 8.0). (D) Cathodal polarization in PPADS-treated cells at high pHe. (E) Untreated cells show randomization at pHe 7.0 and strong cathodal polarization at pHe 8.0. (F) Graph showing percentage of cathodal polarization at different pHe values. Different symbols represent different treatments.
Mentions: Finally, we tested different pH conditions for the pharmacological treatments affecting directionality. We focused on the inhibitions of GPCR and purinergic signaling. For the treatments that cause ­reversal at normal pHe (suramin and gallein), we observed anodal polarization at pHe 6.6, 7.0, and 7.8, with restoration of cathodal polarization at pHe 8.0 (Figure 6, A, B, and F). This suggests that the threshold for cathodal polarization can be pushed toward alkaline pHe values when GPCR and purinergic signaling is inhibited. For the treatments that cause randomization at neutral pHe (PTX and PPDS), we found anodal polarization at low pHe and cathodal polarization at high pHe (Figure 6, C, D, and F). Considering that randomization could be an intermediate step when switching from anodal to cathodal polarization, we predicted that a mildly acidic pHe would cause randomization in untreated cells. This was indeed the case: randomization was found for untreated cells at pHe 7.0. At pHe 8.0, on the other hand, cathodal polarization was 10% more efficient than at normal pHe (Figure 6, E and F).

Bottom Line: By contrast, we found a crucial role for extracellular pH as well as G protein coupled-receptor (GPCR) or purinergic signaling in the control of directionality.Overall our work puts forward a model in which the EF uses distinct polarization pathways.The cathodal pathway involves GPCR/purinergic signaling and is dominant over the anodal pathway at neutral pH.

View Article: PubMed Central - PubMed

Affiliation: Center for Systems Biology, University of Freiburg, 79104 Freiburg, Germany Renal Division, University Hospital Freiburg, 79106 Freiburg, Germany Spemann Graduate School of Biology and Medicine, University of Freiburg, 79104 Freiburg, Germany BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.

No MeSH data available.