Actin and villin compartmentation during ATP depletion and recovery in renal cultured cells

Kidney Int. 1995 Dec;48(6):1837-45. doi: 10.1038/ki.1995.482.

Abstract

ATP-depletion in renal cultured cells has been used as a model for studying various cytoskeletal and functional alterations induced by renal ischemia. This communication explores the reversibility of these effects utilizing a novel method [1] that depleted ATP (ATP-D) to 2% of control within 30 minutes and caused complete recovery (REC) of ATP in one hour. Under confocal microscopy, ATP-D (30 min) caused thinning of F-actin from the microvilli, cortical region, and basal stress fibers, with the concurrent appearance of intracellular F-actin patches. These changes were more pronounced after 60 minutes of ATP-D. One hour of REC following 30 minutes of ATP-D produced complete recovery of F-actin in each region of the cell. However, after 60 minutes of ATP-D, a heterogeneous F-actin recovery pattern was observed: almost complete recovery of the apical ring and microvilli, thinned cortical actin with occasional breaks along the basolateral membrane, and a dramatic reduction in basal stress fiber density. The time course of cortical actin and actin ring disruption and recovery coincided with a drop recovery in the transepithelial resistance and the cytoskeletal dissociation and reassociation of the Na,K-ATPase. Additionally, the microvilli retracted into the cells during ATP-D, a process that was reversed during REC. Triton extraction and confocal microscopy demonstrated that villin remained closely associated with microvillar actin during both ATP-D and REC. These distinctive regional differences in the responses of F-actin to ATP depletion and repletion in cultured renal epithelial cells may help to clarify some of the differential tubular responses to ischemia and reperfusion in the kidney.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Actins / metabolism*
  • Adenosine Triphosphate / metabolism*
  • Analysis of Variance
  • Animals
  • Carrier Proteins / metabolism*
  • Fluorescent Antibody Technique, Indirect
  • Kidney Tubules, Proximal / cytology
  • Kidney Tubules, Proximal / metabolism*
  • LLC-PK1 Cells
  • Microfilament Proteins / metabolism*
  • Microscopy, Confocal
  • Sodium-Potassium-Exchanging ATPase / metabolism
  • Swine

Substances

  • Actins
  • Carrier Proteins
  • Microfilament Proteins
  • villin
  • Adenosine Triphosphate
  • Sodium-Potassium-Exchanging ATPase