Introductory Chapter: Endoplasmic ReticulumKnowledge and Perspectives

Abstract

The endoplasmic reticulum is one of the most studied and fascinating organelles. It is found in all eukaryotic cells and performs a variety of functions. The organelle was designated by this name by Keith Porter in 1953 on the basis of studies carried out with the electron microscope in cells in tissue culture. Porter was able to differentiate the exoplasm, an adjacent region devoid of organelles, from the neighboring endoplasm. In the endoplasm, he examined a system of interrelated tubules, a reticulum, for this reason, the name “endoplasmic reticulum” (ER). The collaboration between Keith Porter and George Palade showed that ER exists in all eukaryotic cells and that it consists of different but continuous domains, the smooth and rough ER, whose abundance fluctuates between different types of cells. Palade observed on the surface of the rough ER the ribosomes that synthesized secretory proteins. The secretory proteins would cross an intracellular membrane, instead of the plasma membrane. The verification of this concept led to the discovery of the secretion pathway and the conception of intracellular protein binding to various organelles.