The p47 co-factor regulates the ATPase activity of the membrane fusion protein, p97

The highly conserved ATPase p97, a member of the AAA-ATPases, is found in a complex with its co-factor p47 in rat liver cytosol. Previously it had been shown that p97-mediated reassembly of Golgi cisternae from mitotic Golgi fragments requires p47 which mediates the binding of p97 to a Golgi t-SNARE (soluble N-ethylmaleimide-sensitive factor attachment factor receptor), syntaxin 5. Here we show that it also suppresses the ATPase activity of p97 by up to 85% in a dose-dependent and saturable manner suggesting that it has other roles in the membrane fusion cycle.