Symmetrical segregation of potassium channels at cytokinesis

D. Lenzi, K. Radke, M. Wilson

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

To determine how voltage-gated ion channels segregate between sibling cells at cytokinesis, we used a whole-cell patch clamp to measure the electrophysiological phenotypes of siblings within 45 min of division. Recently born siblings in an immortalized line of embryonic retinal cells were identified as pairs of spherical cells adhering to one another. All siblings were electrically coupled when cells were simultaneously voltage clamped, whereas nonsiblings were not coupled. Twelve pairs of siblings were electrically isolated by mechanical separation so that their phenotypes could be measured independently. Cells expressed two principal membrane conductances, delayed rectifier-like (I(K)) and inward rectifier (I(K(IR))) potassium currents. Despite qualitative and quantitative variability in I(K) and I(K(IR)) expression within the population, each cell of a given pair expressed similar steady-state current densities between -110 and +50 mV. We estimated I(K(IR)) slope conductance by blocking the current specifically with 5 mM Cs and calculated I(K(IR)) ratios in siblings and nonsiblings. Three pairs of siblings expressed I(K(IR)) ratios of approximately 1.2, while ratios in three pairs of adhered nonsiblings varied between 1.6 and 5.4. When currents were sampled continuously through cytokinesis by using the perforated-patch recording mode, current amplitude showed no net change within 30 min of division. Because channel number did not appear to change in siblings during this interval, parental channels were inherited by each daughter in proportion to the area of membrane received. Heterogeneity therefore arises after siblings reenter interphase and is not due to the asymmetrical segregation of channels at cytokinesis.

Original languageEnglish (US)
Pages (from-to)675-686
Number of pages12
JournalJournal of Neurobiology
Volume24
Issue number5
StatePublished - 1993

Keywords

  • cell line
  • delayed rectifier
  • electrical coupling
  • inward rectifier
  • patch clamp
  • retinal cell
  • voltage-gated current

ASJC Scopus subject areas

  • Neuroscience(all)

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    Lenzi, D., Radke, K., & Wilson, M. (1993). Symmetrical segregation of potassium channels at cytokinesis. Journal of Neurobiology, 24(5), 675-686.