Cellular components that functionally interact with signaling phospholipase A(2)s.

摘要: Accumulating evidence has suggested that cytosolic phospholipase A(2) (cPLA(2)) and several secretory PLA(2) (sPLA(2)) isozymes are signaling PLA(2)s functionally coupled with downstream cyclooxygenase (COX) for prostaglandin (PG) biosynthesis. Arachidonic acid (AA) released by cPLA(2) sPLA(2)s is supplied to both COX-1 COX-2 in the immediate, predominantly delayed, PG-biosynthetic responses. Vimentin, an intermediate filament component, acts as a functional perinuclear adapter cPLA(2), which C2 domain of associates head vimentin Ca(2+)-sensitive manner. The heparin-binding sPLA(2)-IIA, IID V bind glycosylphosphatidylinositol-anchored heparan sulfate proteoglycan glypican, plays role sorting these into caveolae compartments. Phospholipid scramblase, facilitates transbilayer movement anionic phospholipids, renders cellular membranes more susceptible sPLA(2)s. There cooperation between prior activation required act properly. cPLA(2)-derived AA oxidized 12/15-lipoxygenase, products not only augment induction sPLA(2) expression, but also cause membrane perturbation, leading increased susceptibility sPLA(2)-X, heparin-non-binding isozyme, capable releasing from intact cells absence cofactors. This property attributed its ability avidly hydrolyze zwitterionic phosphatidylcholine, major phospholipid outer plasma membrane. sPLA(2)-V can utilize this route cell types. Taken together, AA-releasing function depends on presence regulatory cofactors interfacial binding differ according type, stimuli, processes, subcellular distributions.