Structure and Function at the Cellular Level

Abstract

(Fig 3, top), attached RNP particles could be prepared by detergent treatment (Fig 3, bottom) (Fig 1), the smooth ER (represented primarily by a large Golgi complex) on the apical side of the nucleus (Fig 4), and the zymogen granules (the presumed sites of temporary intracellular storage of enzymes and zymogens) in the apical region of the cell near the glandular lumen (shown in Fig 5 on the follow¬ ing page).The work started with an attempt at "complete" fractionation of the tissue which was only partial¬ ly successful but established the presence of di¬ gestive enzymes in high concentration in a frac¬ tion consisting mainly of zymogen granules.28 It also showed that the amount of digestive enzymes

Mechanisms for the incorporation of proteins in membranes and organelles.

“…It appears unlikely that so similar strategies as are used by these two classes of proteins for traversing or penetrating cellular membranes and for circulation within the cell (60,155,181,188) have developed independently during the course of evolution . In an early discussion of the role of membrane-bound ribosomes in the synthesis of secretory and ER membrane proteins, Palade (154) intimated that some ER membrane proteins may have served as "ancestral models" for secretory proteins . Indeed, it is reasonable to assume that membrane and secretory proteins, as we know them today, represent elaborations on different stages of a progressive evolutionary development that first led to the insertion of cytoplasmic proteins into membranes and later to the extrusion of portions of these proteins from the cell and their release from the membrane by proteolytic cleavage.…”

A Man for All Seasons: Reflections on the Life and Legacy of George Palade

“…Together, Palade and Siekevitz identified the "microsomes" of Claude (Figures 2 and 3) as fragments of the ER (Palade & Siekevitz 1956a,b Pancreatic exocrine cell. The basal region of the cell between the nucleus (N) and the plasmalemma (CM) is occupied by numerous cisternae of the rough endoplasmic reticulum (RER) and a few mitochondria (M) (shown × 9,000) (from Palade 1966). or from microsomal supernatants (free ribosomes) and the demonstration that these organelles are the cytoplasmic sites of protein synthesis (Kirsch et al 1960). These combined biochemical and morphological studies, mainly on liver and the exocrine pancreas (Figures 2 and 3), had closed the loop between the discovery of ribosomes by electron microscopy and characterization of their function in protein synthesis by biochemistry.…”

“…Electron micrograph of a sectioned pellet of pancreatic microsomes (guinea pig) (shown ×60,000; from Palade 1966). Abbreviations: AR, attached ribosomes; MC, microsomal content; MM, microsomal membrane.…”

“…During the early years the salient points established by this work were the involvement of attached ribosomes in synthesis of secretory proteins and the vectorial transport of proteins from the attached ribosomes to microsomal ER cavities, in collaboration with D. Sabatini and Y. Tashiro (Sabatini et al 1966), and the demonstration that secretory granules represent sites of stored pancreatic enzymes (Greene et al 1963). Electron micrograph of the Golgi region in a pancreatic exocrine cell showing the elements of the Golgi complex (shown ×25,000) (from Palade 1966). Abbreviations: CV, condensing vacuoles; GC, Golgi cisternae; SV, small peripheral, ER-Golgi transport vesicles; TR, transitional elements; LY, lysosome.…”

“…Cell Biology finally makes possible a century old dream: that of analysis of diseases, at the cellular level-the first step toward their final control." Although by this time he had received many prestigious prizes, including the Gairdner Special Award, the Louisa Gross Horwitz Prize of Columbia University, and the Lasker Basic Science Award (Palade 1966), and later received the National Medal of Science, this was quite different. The Nobel is considered the highest of all honors that can be awarded to a scientist and definitely represented the beginning of a new phase of his career.…”