PMID:9490642

Citation	Fayard, JM, Tessier, C, Pageaux, JF, Lagarde, M and Laugier, C (1998) Nuclear location of PLA2-I in proliferative cells. J. Cell. Sci. 111 ( Pt 7):985-94
Abstract	We have previously demonstrated that pancreatic PLA2 (PLA2-I) stimulates the proliferation of UIII cells, a stromal cell line derived from normal rat uterus. In order to gain further insight into the mechanism of action of PLA2-I, we have investigated the intracellular processing of PLA2-I. Either highly proliferative or growth arrested UIII cells were analyzed. Growth arrested cells were obtained from a contact inhibited monolayer or from aristolochic acid-treated cultures. Using cellular fractionation, western blotting, immunocytochemistry and confocal microscopy, we demonstrate that endogenous PLA2-I was mainly located in the nucleus in highly proliferative cells whereas its location was cytoplasmic in non proliferative cells. When non confluent UIII cells were incubated with nanomolar amounts of exogenous PLA2-I, the enzyme was internalized and, in the majority of cells, appeared within the nucleus. Both internalization and nuclear location of exogenous PLA2-I were suppressed by the addition of aristolochic acid to the culture medium. Binding experiments performed on purified nuclear preparations showed the presence of specific cooperative binding sites for PLA2-I. Collectively our data suggest that the proliferative effect exerted by pancreatic PLA2 in UIII cells is mediated by a direct interaction of the enzyme at the nuclear level. Putative mechanisms and targets are discussed.
Links	PubMed
Keywords	Animals; Binding Sites; Cell Division; Cell Line; Cell Nucleus/enzymology; Cell Nucleus/metabolism; Cell Nucleus/ultrastructure; Enzyme Activation; Female; Isoenzymes/metabolism; Phospholipases A/metabolism; Phospholipases A2; Protein Binding; Rats; Stromal Cells; Subcellular Fractions/enzymology; Subcellular Fractions/metabolism; Subcellular Fractions/ultrastructure; Uterus
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
RAT:PLPL9		GO:0090435: protein localization to nuclear envelope	ECO:0000314:		P		Figure 4 shows that when PLA2-I was stained, fluorescence was only detected in the nucleus using confocal and phase contrast microscopy. There was no fluorescence and therefore no protein present anywhere else in the cell.	complete CACAO 9820

References

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