Inhibition of the membrane fusion machinery prevents exit from the TGN and proteolytic processing by furin
A M Band1, J Määttä, L Kääriäinen
1Department of Biosciences, Division of Biochemistry, Viikki Biocenter, University of Helsinki, Finland. arja.band@helsinki.fi
Abstract:
The Semliki Forest virus (SFV) glycoprotein precursor p62 is processed to the E2 and E3 during the transport from the trans-Golgi network (TGN) to the cell surface. We have studied the regulation of the membrane fusion machinery (Rab/N-ethylmaleimide (NEM)-sensitive fusion protein (NSF)/soluble NSF attachment protein (SNAP)-SNAP receptor) in this processing. Activation of the disassembly of this complex with recombinant NSF stimulated the cleavage of p62 in permeabilized cells. Inactivation of NSF with a mutant alpha-SNAP(L294A) or NEM treatment inhibited processing of p62. Rab GDP dissociation inhibitor inhibited the cleavage. Inactivation of NSF blocks the transport of SFV glycoproteins and vesicular stomatitis virus G-glycoprotein from the TGN membranes to the cell surface. The results support the conclusion that inhibition of membrane fusion arrests p62 in the TGN and prevents its processing by furin.
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