The Lysosome and Lysosomal Storage Disorders (LSD). Part I: Historical, Physiological and Pathological Considerations. Serge Melançon, MD January 2010. Synopsis (Part 1A). Historical notes and scientific partners The endosomal-lysosomal system The ‘synthetic’ pathway
Part I: Historical, Physiological and Pathological Considerations
Serge Melançon, MD
In 1955, Belgian scientist Christian de Duve observed that the cells released an enzyme called acid phosphatase in much larger amounts when they were repeatedly frozen and thawed before centrifugation
de Duve C (1975) Exploring cells with a centrifuge. Science 189, 186-194
Lysosomes are spherical organelles contained by a single layer membrane, though their size and shape vary to some extent.
Several hundred lysosomal structures can be seen in the above phase micrograph
The RER is where hydrolytic
enzymes are manufactured
before being transported to
the Golgi apparatus (complex),
where they undergo additional processing and are transformed from an inactive to an active state
1 Modification of complex molecules (such as proteins) by the addition of sugars (glycosylation)
2 Proteolysis of peptide molecules which makes them become active
3 Sorting of molecules for either, transport out of the cell, incorporation in the cell membrane, or transport to another part of the cell
The mitochondria are essential in the production of energy (via adenosine triphosphase; ATP) and lipid biosynthesis
That convert hydrogen peroxide to water and render potentially toxic substances safe for the cell
And also initiate the production of phospholipids, which are typically used to build up cell membranes.
(At this early stage they are inactive)
*Soluble N-ethylmaleimide-sensitive fusion protein (NSF) attachment protein receptors
from endosomes to the trans-Golgi network.
Working model of Retromer