NSF and SNAP are present on adrenal chromaffin granules

Abstract

N-ethylmaleimide sensitive fusion protein (NSF) and soluble NSF attachment proteins (SNAPs) are involved in many vesicular transport steps. It has been proposed that SNAPs and NSF associate with their membrane receptors only when vesicles dock on the target membrane. Analysis of NSF and α-SNAP distribution in fractionation of organelles from adrenal medulla indicated that a substantial amount of both proteins distributed with chromaffin granules. Further fractionation of intact granules and lysed granu e membranes showed exact overlap of NSF and α-SNAP distribution with chromaffin granules. These results suggest that NSF and α-SNAP are associated with chromaffin granules and support the idea that they function prior to docking of the granules on the plasma membrane.