Different roles of membrane potentials in electrotaxis and chemotaxis of Dictyostelium cells

Run chi Gao, Xiao dong Zhang, Yao hui Sun, Yoichiro Kamimura, Alex Mogilner, Peter N. Devreotes, Min Zhao

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

Many types of cells migrate directionally in direct current (DC) electric fields (EFs), a phenomenon termed galvanotaxis or electrotaxis. The directional sensing mechanisms responsible for this response to EFs, however, remain unknown. Exposing cells to an EF causes changes in plasma membrane potentials (V m). Exploiting the ability of Dictyostelium cells to tolerate drastic V m changes, we investigated the role of V m in electrotaxis and, in parallel, in chemotaxis. We used three independent factors to control V m: extracellular pH, extracellular [K +], and electroporation. Changes in V m were monitored with microelectrode recording techniques. Depolarized V m was observed under acidic (pH 5.0) and alkaline (pH 9.0) conditions as well as under higher extracellular [K +] conditions. Electroporation permeabilized the cell membrane and significantly reduced the V m, which gradually recovered over 40 min. We then recorded the electrotactic behaviors of Dictyostelium cells with a defined V m using these three techniques. The directionality (directedness of electrotaxis) was quantified and compared to that of chemotaxis (chemotactic index). We found that a reduced V m significantly impaired electrotaxis without significantly affecting random motility or chemotaxis. We conclude that extracellular pH, [K +], and electroporation all significantly affected electrotaxis, which appeared to be mediated by the changes in V m. The initial directional sensing mechanisms for electrotaxis therefore differ from those of chemotaxis and may be mediated by changes in resting V m·.

Original languageEnglish (US)
Pages (from-to)1251-1256
Number of pages6
JournalEukaryotic Cell
Volume10
Issue number9
DOIs
StatePublished - Sep 2011

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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