ADF/cofilin mediates actin cytoskeletal alterations in LLC-PK cells during ATP depletion

Am J Physiol Renal Physiol. 2003 Apr;284(4):F852-62. doi: 10.1152/ajprenal.00210.2002. Epub 2002 Dec 3.

Abstract

Ischemic injury induces actin cytoskeleton disruption and aggregation, but mechanisms affecting these changes remain unclear. To determine the role of actin-depolymerizing factor (ADF)/ cofilin participation in ischemic-induced actin cytoskeletal breakdown, we utilized porcine kidney cultured cells, LLC-PK(A4.8), and adenovirus containing wild-type (wt), constitutively active, and inactive Xenopus ADF/cofilin linked to green fluorescence protein [XAC(wt)-GFP] in an ATP depletion model. High adenoviral infectivity (70%) in LLC-PK(A4.8) cells resulted in linearly increasing XAC(wt)-GFP and phosphorylated (p)XAC(wt)-GFP (inactive) expression. ATP depletion rapidly induced dephosphorylation, and, therefore, activation, of endogenous pcofilin as well as pXAC(wt)-GFP in conjunction with the formation of fluorescent XAC(wt)-GFP/actin aggregates and rods. No significant actin cytoskeletal alterations occurred with short-term ATP depletion of LLC-PK(A4.8) cells expressing GFP or the constitutively inactive mutant XAC(S3E)-GFP, but cells expressing the constitutively active mutant demonstrated nearly instantaneous actin disruption with aggregate and rod formation. Confocal image three-dimensional volume reconstructions of normal and ATP-depleted LLC-PK(A4.8) cells demonstrated that 25 min of ATP depletion induced a rapid increase in XAC(wt)-GFP apical and basal signal in addition to XAC-GFP/actin aggregate formation. These data demonstrate XAC(wt)-GFP participates in ischemia-induced actin cytoskeletal alterations and determines the rate and extent of these ATP depletion-induced cellular alterations.

Publication types

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

MeSH terms

  • Actin Depolymerizing Factors
  • Actins / metabolism*
  • Adenosine Triphosphate / metabolism
  • Adenoviridae / genetics
  • Animals
  • Antimycin A / pharmacology
  • Cell Line
  • Cell Membrane / metabolism
  • Cytoskeleton / drug effects
  • Cytoskeleton / metabolism*
  • Destrin
  • Gene Transfer Techniques
  • Green Fluorescent Proteins
  • Kidney / cytology
  • Kidney / drug effects
  • Kidney / metabolism*
  • LLC-PK1 Cells
  • Luminescent Proteins / genetics
  • Mice
  • Microfilament Proteins / genetics
  • Microfilament Proteins / metabolism*
  • Microscopy, Fluorescence
  • Mutagenesis, Site-Directed
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • Protein Transport / drug effects
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Swine
  • Xenopus

Substances

  • Actin Depolymerizing Factors
  • Actins
  • Destrin
  • Dstn protein, mouse
  • Luminescent Proteins
  • Microfilament Proteins
  • Protein Isoforms
  • Recombinant Fusion Proteins
  • Green Fluorescent Proteins
  • Antimycin A
  • Adenosine Triphosphate