Nuclear translocation of cytosolic phospholipase A2 is induced by ATP depletion.
Phospholipase A(2) (PLA(2)) enzymes may play a role in cellular injury due to ATP depletion. Renal Madin-Darby canine kidney cells were subjected to ATP depletion to assess the effects of cellular energy metabolism on cytosolic PLA(2) (cPLA(2)) regulation. ATP depletion results in a decrease in soluble cPLA(2) activity and an increase in membrane-associated activity, which is reversed upon restoration of ATP levels by addition of dextrose. In ATP-depleted cells cPLA(2) mass shifts from cytosol to nuclear fractions. GFP-cPLA(2) is localized at the nuclear membrane of stably transfected ATP-depleted LLC-PK(1) cells under conditions where [Ca(2+)](i) is known to increase. cPLA(2) translocation does not occur if the increase in [Ca(2+)](i) increase is inhibited. If [Ca(2+)](i) is allowed to increase when ATP is depleted and the cells are then lysed, cPLA(2) remains associated with nuclear fractions even if the homogenate [Ca(2+)] is markedly reduced. In contrast, cPLA(2), which becomes associated with the nucleus when [Ca(2+)](i) is increased using ionophore, readily dissociates from the nuclear fractions of ATP-replete cells upon reduction of homogenate [Ca(2+)]. Okadaic acid inhibits the ATP depletion-induced association of cPLA(2) with nuclear fractions. Thus energy deprivation results in [Ca(2+)]-induced nuclear translocation, which is partially prevented by a phosphatase inhibitor.
Sheridan
A M
AM
Medical Service, Massachusetts General Hospital and the Departments of Medicine Harvard Medical School, Charlestown, Massachusetts 02129, USA. asheridan@partners.org
Sapirstein
A
A
Lemieux
N
N
Martin
B D
BD
Kim
D K
DK
Bonventre
J V
JV
D021581:Active Transport, Cell Nucleus; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D002467:Cell Nucleus / Q000201:enzymology* / Q000378:metabolism; D003486:Cyanides / Q000494:pharmacology; D003600:Cytosol / Q000201:enzymology*; D003847:Deoxyglucose / Q000494:pharmacology; D004285:Dogs; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D049452:Green Fluorescent Proteins; D006863:Hydrogen-Ion Concentration; D007668:Kidney / Q000201:enzymology*; D008164:Luminescent Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D019319:Okadaic Acid / Q000494:pharmacology; D010741:Phospholipases A / Q000378:metabolism*; D054467:Phospholipases A2; D010957:Plasmids / Q000378:metabolism; D013997:Time Factors; D014162:Transfection
D003486:Cyanides; D004791:Enzyme Inhibitors; D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins; D019319:Okadaic Acid; D000001:Calcimycin; D004533:Egtazic Acid; D000255:Adenosine Triphosphate; D003847:Deoxyglucose; D010741:Phospholipases A; D054467:Phospholipases A2; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D002118:Calcium