title: pH nanoenvironment at the surface of single melanoma cells.
abstract: Extracellular pH and the Na(+)/H(+) exchanger (NHE1) modulate tumor cell migration. Yet, the pH nanoenvironment at the outer surface of the cell membrane (pH(em)) where cell/matrix interaction occurs and matrix metalloproteinases work was never measured. We present a method to measure this pH nanoenvironment using proton-sensitive dyes to label the outer leaflet of the plasma membrane or the glycocalyx of human melanoma cells. Polarized cells generate an extracellular proton gradient at their surface that increases from the rear end to the leading edge of the lamellipodium along the direction of movement. This gradient collapses upon NHE1 inhibition by HOE642. NHE1 stimulation by intracellular acidification increases the difference in pH(em) between the tips of lamellipodia and the cell body in a Na(+) dependent way. Thus, cells create a pH nanoenvironment that promotes cell migration by facilitating cell adhesion at their front and the release of cell/matrix contacts at their rear part.
authors.affiliation: Institute of Physiology II, University of Münster, Germany. cmstock@uni-muenster.de
authors.forename: Christian
authors.initials: C
authors.lastname: Stock
authors.forename: Markus
authors.initials: M
authors.lastname: Mueller
authors.forename: Hermann
authors.initials: H
authors.lastname: Kraehling
authors.forename: Sabine
authors.initials: S
authors.lastname: Mally
authors.forename: Josette
authors.initials: J
authors.lastname: Noël
authors.forename: Claudia
authors.initials: C
authors.lastname: Eder
authors.forename: Albrecht
authors.initials: A
authors.lastname: Schwab
mesh_terms: D027682:Cation Transport Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D002465:Cell Movement; D002470:Cell Survival; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008545:Melanoma / Q000378:metabolism* / Q000473:pathology*; D000074082:Sodium-Hydrogen Exchanger 1; D017923:Sodium-Hydrogen Exchangers / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D027682:Cation Transport Proteins; C490998:SLC9A1 protein, human; D000074082:Sodium-Hydrogen Exchanger 1; D017923:Sodium-Hydrogen Exchangers