Article

Assembly of an intact Golgi complex requires phospholipase A2 (PLA2) activity, membrane tubules, and dynein-mediated microtubule transport.

Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
Biochemical and Biophysical Research Communications (impact factor: 2.48). 09/2009; 389(3):473-7. DOI:10.1016/j.bbrc.2009.08.173
Source: PubMed

ABSTRACT Previous studies have shown that treatment of mammalian cells with phospholipase A(2) (PLA(2)) antagonists cause the normally interconnected Golgi ribbon to break up into large fragments of stacked Golgi cisternae ("mini-stacks") that remain located in the juxtanuclear region. Using the reversible PLA(2) antagonist, ONO-RS-082 (ONO) and live-cell, time-lapse microscopy to image the Golgi reassembly process, we found that Golgi mini-stacks underwent a burst of membrane tubule formation following washout of ONO: before washout only 4.3+/-3.8 tubules/cell/10 min were formed, whereas after washout 29.9+/-11.9 tubules/cell/10 min formed. These membranes tubules formed bridges between physically separate mini-stacks, thus mediating their coalescence into intact Golgi ribbons. Formation of inter-stack tubules and an intact Golgi ribbon was also facilitated by microtubules because treatment with nocodazole significantly inhibited both processes. This microtubule-dependent process was also dependent on dynein because the dynein inhibitor nordihydroguaiaretic acid (NDGA) inhibited reassembly. These studies show that a late stage of Golgi assembly occurs via membrane tubules, whose formation is dependent on PLA(2) activity and microtubules. Considering these results together, we concluded that the maintenance and assembly of normal Golgi architecture is dependent on the PLA(2)-mediated, dynamic formation of inter-Golgi membrane tubules.

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Keywords

dynamic formation
 
dynein inhibitor nordihydroguaiaretic acid
 
Golgi assembly
 
Golgi cisternae
 
Golgi mini-stacks
 
Golgi reassembly process
 
intact Golgi ribbon
 
intact Golgi ribbons
 
inter-Golgi membrane tubules
 
interconnected Golgi ribbon
 
large fragments
 
mammalian cells
 
membrane tubule formation
 
microtubule-dependent process
 
normal Golgi architecture
 
phospholipase A(2)
 
PLA(2)-mediated
 
processes
 
reversible PLA(2)
 
separate mini-stacks