Cytosolic phospholipase A(2) activity associated with nuclei is not inhibited by arachidonyl trifluoromethyl ketone in macrophages stimulated with receptor-recognized forms of alpha(2)-maoroglobulin

Citation
Uk. Misra et Sv. Pizzo, Cytosolic phospholipase A(2) activity associated with nuclei is not inhibited by arachidonyl trifluoromethyl ketone in macrophages stimulated with receptor-recognized forms of alpha(2)-maoroglobulin, ARCH BIOCH, 379(1), 2000, pp. 153-160
Citations number
55
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biochemistry & Biophysics
Journal title
ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS
ISSN journal
0003-9861 → ACNP
Volume
379
Issue
1
Year of publication
2000
Pages
153 - 160
Database
ISI
SICI code
0003-9861(20000701)379:1<153:CPAAAW>2.0.ZU;2-I
Abstract
We have studied the translocation of cytosolic phospholipase A(2) (cPLA(2)) to nuclei in macrophages stimulated with receptor-recognized forms of alph a(2)-macroglobulin (alpha(2)M*). Translocation of phosphorylated cPLA(2) to nuclei was determined by immunoprecipitation of cPLA(2) in P-32(i)-labeled cells. The identity of cPLA(2) was established by comparing its mobility o n gels with an authentic cPLA(2) standard. cPLA(2) activity was quantified by measuring the release of [C-14]arachidonic acid from the substrate 1-pal mitoyl-2-[1-C-14]arachidonyl-sn-glycerophosphatidylcholine. alpha(2)M* caus ed a two- to threefold increase in cPLA(2) phosphorylation and its transloc ation to nuclei. The p38 MAPK inhibitor SB203580, PKC inhibitor chelerythri n, or depletion of intracellular Ca2+ profoundly decreased cPLA(2) activity in nuclei isolated from agonist-stimulated cells. The requirement for Ca2, PKC, and p38 MAPK activation appears to be of major importance for nuclea r cPLA(2) activity. In contrast to cellular cPLA(2) activity, nuclear cPLA( 2) activity was not inhibited by arachidonyl trifluoromethyl ketone (AACOCF (3)) in agonist-stimulated cells. It is concluded that the association of c PLA(2) with nuclear membranes in agonist-stimulated cells modifies the acti vity and the sensitivity of the enzyme to inhibition by AACOCF(3) in this p hospholipid environment. (C) 2000 Academic Press.