The secretory membrane system studied in real-time

The discovery and development of green fluorescent protein (GFP) from the j ellyfish, Aequorea victoria, has revolutionized studies on protein localiza tion and dynamics by allowing direct observation of a protein's life histor y and pathway in living cells, previously only deduced from genetic, bioche mical, or immunolabeling studies. Applied to the secretory membrane system, which regulates delivery of newly synthesized proteins and lipids to the c ell surface, GFP-based studies are providing important new insights into th e maintenance and biogenesis of organelles, as well as the origin, pathway, and fate of secretory transport intermediates.