NSF AND SNAP ARE PRESENT ON ADRENAL CHROMAFFIN GRANULES

N-ethylmaleimide sensitive fusion protein (NSF) and soluble NSF attach ment 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 alpha-SNAP distribution in fractionation of organelles from ad renal medulla indicated that a substantial amount of both proteins dis tributed with chromaffin granules. Further fractionation of intact gra nules and lysed granule membranes showed exact overlap of NSF and alph a-SNAP distribution with chromaffin granules. These results suggest th at NSF and alpha-SNAP are associated with chromaffin granules and supp ort the idea that they function prior to docking of the granules on th e plasma membrane. (C) 1997 Federation of European Biochemical Societi es.