Syntaxin 5 Is a Common Component of the NSF- and p97-Mediated Reassembly Pathways of Golgi Cisternae from Mitotic Golgi Fragments In Vitro

A cell-free system that mimics the reassembly of Golgi stacks at the end of mitosis requires two ATPases, NSF and p97, to rebuild Golgi cisternae. Morphological studies now show that α-SNAP, a component of the NSF pathway, can inhibit the p97 pathway, whereas p47, a component of the p97 pathway, can inhibit the NSF pathway. Anti-syntaxin 5 antibodies and a soluble, recombinant syntaxin 5 inhibited both pathways, suggesting that this t-SNARE is a common component. Biochemical studies confirmed this, showing that p47 binds directly to syntaxin 5 and competes for binding with α-SNAP. p47 also mediates the binding of p97 to syntaxin 5 and so plays an analogous role to α-SNAP, which mediates the binding of NSF.