secreted proteins bound for different intracellular destinations.
Membrane vesicles derived from this organelle may be targeted to the
lysosome or the apical or basolateral surfaces of a polarized cell, or
they may be held in the cytoplasm awaiting a specific signal for
exocytosis. Here, Choukroun and colleagues show that Golgi structure
and function depend on local lipid metabolism. Phospholipase A2 (PLA2)
cleaves phospholipids to generate arachidonic acid, the precursor of
many bioactive lipids, as well as lysophospholipids, which are thought
to regulate membrane fusion during protein secretion.
Choukroun et
al. report that PLA2 associates with the cell’s Golgi fraction, and
they show that overexpression of the enzyme disrupts the organization
of the Golgi apparatus and specifically blocks the trafficking of
certain constitutively secreted proteins, while allowing other cargo
proteins to be packaged normally into regulated secretory vesicles.
The fragmentation of the Golgi apparatus seen in PLA2-overexpressing
cells is similar to a change that occurs during mitosis. The authors
indicate that PLA2 activity rises during this period of the cell cycle,
and they suggest that the accumulation of phospholipid metabolites in
the Golgi membrane causes this organelle to vesiculate during cell
division.
###
Journal
Journal of Clinical Investigation
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