Inhibition of endosome fusion by phospholipase A2 (PLA2) inhibitors points to a role for PLA2 in endocytosis.
AUTOR(ES)
Mayorga, L S
RESUMO
Fusion of intracellular membrane-bound compartments is a common step in the transport of macromolecules along the endocytic and secretory pathways. A large number of factors active in the fusion process or its regulation have been identified; however, the actual sequence of events leading to membrane fusion is still unknown. In this study, we have assessed a possible role for PLA2 in endosome fusion by using an in vitro reconstitution assay and by examining endocytosis in intact cells. Several PLA2 inhibitors blocked endosome fusion in a broken-cell preparation. Inhibition was reversed by addition of arachidonic acid. At the electron microscope level, endosome clusters were observed even in the presence of inhibitors; however, actual fusion between endosomes was largely reduced. Fusion frequency increased upon the addition of arachidonic acid. A membrane-permeable PLA2 inhibitor blocked mixing of ligands internalized sequentially but did not affect internalization. The results indicate that vesicle fusion along the endocytic pathway requires a PLA2 activity. The effect of this activity would be, at least in part, mediated by arachidonic acid release.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=47753Documentos Relacionados
- Atividade enzimática dos subtipos de fosfolipase A2 (PLA2) em cultura primária de neurônios
- Crystal Structure of a Class XIB Phospholipase A2 (PLA2): RICE (ORYZA SATIVA) ISOFORM-2 PLA2 AND AN OCTANOATE COMPLEX*
- Trinucleotide repeat polymorphism at the human pancreatic phospholipase A-2 gene (PLA2)
- Inhibition of rab5 GTPase activity stimulates membrane fusion in endocytosis.
- Activation of phospholipase PLA2 actvity in Ricinus communis leaves in response to mechanical wounding