Soluble N-ethylmaleimide-sensitive fusion attachment proteins (SNAPs) bind to a multi-SNAP receptor complex in Golgi membranes

Soluble N-ethylmaleimide-sensitive fusion attachment proteins (SNAPs) are required for the binding of N-ethylmaleimide-sensitive fusion protein (NSF) to Golgi membranes and are, therefore, required for intra-Golgi transport. We report the existence of distinct α/β-SNAP and γ-SNAP-binding sites in Golgi membranes that appear to be part of the same receptor complex. Cross- linking studies with α-SNAP demonstrate that an integral membrane protein of between 30-40 kDa is the α-SNAP binding component of the multi-SNAP receptor complex. These data suggest that SNAPs function by independently binding to a multi-SNAP membrane-receptor complex, thereby activating them to serve as adaptors for the targeting of NSF.