3.25 in. x 4 in. Lantern Slides, Original Magnification: x17,000, and Pulse chase experiments, carried out by Jamieson and Palade, defined the kinetics and pathway of intracellular transport of newly synthesized proteins in guinea pig pancreatic slices in vitro. The 3 min pulse consisted of preincubation in the cold in a leucine-free medium containing tritiated leucine, followed by warming up to 37 for 3 min. Chase incubations followed by incubation in medium containing an excess of "cold" leucine, fixation at indicated times, and processing for EM autoradiography. Historic details in the Nobel Lecture 1974 by Dr. Palade.
3.25 in. x 4 in. Lantern Slides, Original Magnification: x16,000, and Protein synthesis is not required for any step in the secretory pathway beyond initial synthesis of exportable proteins. ATP is need for RER to Golgi transport, not for concentration, but is required for stimulated exocytosis.
3.25 in. x 4 in. Lantern Slides and These studies showed that the rate of protein synthesis, rate of drainage of the RER to the Golgi and the overall transit rate over the secretory pathway was not accelerated by prior secretagogue release of all preformed zymogen granules. Furthermore, secretory proteins were not rerouted into the cytosol as had been proposed by others.
Publisher:
Yale University School of Medicine
Subject (Name):
Jamieson, James D
Subject (Topic):
Guinea pig pancreatic slice stimulated in vitro EMAR
3.25 in. x 4 in. Lantern Slides, Intracellular transport from the RER to the Golgi periphery requires ATP but not continued protein synthesis. The evidence suggested that the energy-requiring step may be located at the transitional elements of the RER and may be involved in the pinching off of Golgi transport vesicles., and Original Magnification: x10,000
3.25 in. x 4 in. Lantern Slides, Original Magnification: x10,000, and Protein transport from the RER to the final steps of exocytosis does not require ongoing protein synthesis as determined in these studies. We postulated that synthesis of new proteins such as membrane proteins, in the short term, is not required. Recycled zymogen granule membrane may provide the needed reservoir of membranes for construction of new zymogen granules.