Abstract
Intracellular free Ca2+ ([Ca2+](i)) is a pivotal signalling element in cell migration and is thought to be required for chemotaxis of Dictyostelium. Ca2+ signalling may also be important for electrotaxis. However this suggestion has been controversial. We show that electric fields direct Dictyostelium cells to migrate cathodally and increase [Ca2+] i in Dictyostelium cells, as determined by Fluo-3 AM imaging and Ca-45(2+) uptake. Omission of extracellular Ca2+([Ca2+](e)) and incubation with EGTA abolished the electric-field-stimulated [Ca2+](i) rise and directional cell migration. This suggests a requirement for [Ca2+](e) in the electrotactic response. Deletion of iplA, a gene responsible for chemoattractant-induced [ Ca2+](i) increase, had only a minor effect on the electric-field-induced [Ca2+](i) rise. Moreover, iplA-null Dictyostelium cells showed the same electrotactic response as wild-type cells. Therefore, iplA-independent Ca2+ influx is necessary for electrotactic cell migration. These results suggest that the [ Ca2+](i) regulatory mechanisms induced by electric fields are different from those induced by cAMP and folic acid in Dictyostelium cells. Different roles of the iplA gene in chemoattractant-induced and electrically induced Ca2+ signalling, and different effects of [ Ca2+](i) elevation on chemotaxis and electrotaxis indicate that the chemoattractant and electric cues activate distinctive initial signalling elements.
Original language | English |
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Pages (from-to) | 4741-4748 |
Number of pages | 8 |
Journal | Journal of Cell Science |
Volume | 119 |
Issue number | 22 |
Early online date | 8 Nov 2006 |
DOIs | |
Publication status | Published - 15 Nov 2006 |
Keywords
- Calcium
- Cell migration
- Dictyostelium
- iplA
- Electrotaxis