title: Spontaneous and electric field-controlled front-rear polarization of human keratinocytes.
abstract: It has long been known that electrical fields (EFs) are able to influence the direction of migrating cells, a process commonly referred to as electrotaxis or galvanotaxis. Most studies have focused on migrating cells equipped with an existing polarity before EF application, making it difficult to delineate EF-specific pathways. Here we study the initial events in front-rear organization of spreading keratinocytes to dissect the molecular requirements for random and EF-controlled polarization. We find that Arp2/3-dependent protrusive forces and Rac1/Cdc42 activity were generally required for both forms of polarization but were dispensable for controlling the direction of EF-controlled polarization. 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. The normal direction of polarization toward the cathode was reverted by lowering extracellular pH. Polarization toward the anode was also seen at neutral pH when GPCR or purinergic signaling was inhibited. However, the stepwise increase of extracellular pH in this scenario led to restoration of cathodal polarization. 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.
authors.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.
authors.forename: Deniz
authors.initials: D
authors.lastname: Saltukoglu
authors.affiliation: Center for Systems Biology, University of Freiburg, 79104 Freiburg, Germany Renal Division, University Hospital Freiburg, 79106 Freiburg, Germany.
authors.forename: Julian
authors.initials: J
authors.lastname: Grünewald
authors.affiliation: Center for Systems Biology, University of Freiburg, 79104 Freiburg, Germany Renal Division, University Hospital Freiburg, 79106 Freiburg, Germany.
authors.forename: Nico
authors.initials: N
authors.lastname: Strohmeyer
authors.affiliation: BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany Institute for Computer Science, Faculty of Engineering, University of Freiburg, 79110 Freiburg, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Bensch
authors.affiliation: BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany Institute of Physiology II, University of Freiburg, 79106 Freiburg, Germany.
authors.forename: Maximilian H
authors.initials: MH
authors.lastname: Ulbrich
authors.affiliation: BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany Institute for Computer Science, Faculty of Engineering, University of Freiburg, 79110 Freiburg, Germany.
authors.forename: Olaf
authors.initials: O
authors.lastname: Ronneberger
authors.affiliation: Center for Systems Biology, University of Freiburg, 79104 Freiburg, Germany Renal Division, University Hospital Freiburg, 79106 Freiburg, Germany BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany Imagine Institute, Paris Descartes University-Sorbonne Paris Cité, 75015 Paris, France matias.simons@institutimagine.org.
authors.forename: Matias
authors.initials: M
authors.lastname: Simons
mesh_terms: D051376:Actin-Related Protein 2-3 Complex / Q000037:antagonists & inhibitors / Q000378:metabolism; D002461:Cell Line, Transformed; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D016764:Cell Polarity / Q000187:drug effects / Q000502:physiology*; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D004558:Electric Stimulation; D004560:Electricity; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007211:Indoles / Q000494:pharmacology; D015603:Keratinocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D051376:Actin-Related Protein 2-3 Complex; C543733:CK-0944666; D007211:Indoles