Calcium dependence of integrity of the actin cytoskeleton of proximal tubule cell microvilli

Keizo Sogabe, Nancy F. Roeser, Julie A. Davis, Saul Nurko, Manjeri A. Venkatachalam, Joel M. Weinberg

Research output: Contribution to journalArticlepeer-review

34 Scopus citations


To better define the role of Ca2+ in pathophysiological alterations of the proximal tubule microvillus actin cytoskeleton, we studied freshly isolated tubules in which intracellular free Ca2+ was equilibrated with highly buffered, precisely defined medium Ca2+ levels using a combination of the metabolic inhibitor, antimycin, and the ionophore, ionomycin, in the presence of glycine, to prevent lethal membrane damage and resulting nonspecific changes. Increases of Ca2+ to ≥ 10 μM were sufficient to initiate concurrent actin depolymerization, fragmentation of F-actin into forms requiring high-speed centrifugation for recovery, redistribution of villin to sedimentable fractions, and structural microvillar damage consisting of severe swelling and fragmentation of actin cores. These observations implicate Ca2+-dependent, villin-mediated actin cytoskeletal disruption in tubule cell microvillar damage under conditions conceivably present during pathophysiological states. However, despite prior evidence for cytosolic free Ca2+ increases of the same order of magnitude and similar structural microvillar alterations, Ca2+- and villin-mediated events did not appear to account for the initial microvillar damage that occurs during ATP depletion induced by antimycin alone or hypoxia.

Original languageEnglish (US)
Pages (from-to)F292-F303
JournalAmerican Journal of Physiology
Issue number2 PART 2
StatePublished - 1996


  • Acute renal failure
  • Fodrin
  • Glycine
  • Hypoxia
  • Kidney
  • Rabbit
  • Villin

ASJC Scopus subject areas

  • Physiology (medical)


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