Author:
Capestrano Mariagrazia,Mariggio Stefania,Perinetti Giuseppe,Egorova Anastasia V.,Iacobacci Simona,Santoro Michele,Di Pentima Alessio,Iurisci Cristiano,Egorov Mikhail V.,Di Tullio Giuseppe,Buccione Roberto,Luini Alberto,Polishchuk Roman S.
Abstract
Earlier studies have demonstrated that membrane tubule–mediated transport events in biosynthetic and endocytic routes require phospholipase A2 (PLA2) activity. Here we show that cytosolic phospholipase A2ε (cPLA2ε) is targeted to the membrane compartments of clathrin-independent (CI) endocytic route via a C-terminal stretch of positively charged aminoacids, which allows the enzyme to interact with phosphoinositide lipids (especially PI(4,5)P2) enriched in CI endosomes. cPLA2ε ablation suppressed the formation of tubular elements that carry internalized CI cargoes, such as MHC-I, CD147 and CD55, back to the cell surface and, therefore, caused their intracellular retention. The ability of cPLA2ε to support recycling through tubule formation relies on the catalytic activity of the enzyme, as the inactive cPLA2εS420A mutant was not able to recover either tubule growth or transport from CI endosomes. Taken together, our findings indicate cPLA2ε as a new important regulator of trafficking processes within the CI endocytic/recycling route. The affinity of cPLA2ε for this pathway supports a new hypothesis that different PLA2 enzymes utilize selective targeting mechanisms to regulate tubule formation locally during specific trafficking steps in the secretory and/or endocytic systems.
Publisher
The Company of Biologists
Cited by
30 articles.
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