Login processing...

Trial ends in Request Full Access Tell Your Colleague About Jove

18.6: Maturation of Endosomes

JoVE Core
Cell Biology

A subscription to JoVE is required to view this content. Sign in or start your free trial.

Maturation of Endosomes

18.6: Maturation of Endosomes

The early endosome containing internalized molecules matures through transformations in its location, morphology, intraluminal pH, and membrane protein composition. Together, these changes result in a more acidic late endosome that contains multiple intraluminal vesicles; therefore, the late endosome is also called a multivesicular body (MVB).

Changes in location

The maturing endosome moves along microtubules from the periphery of the cell towards the perinuclear region. This movement of the endosome is mediated by dynein and kinesin motor proteins. Disruption of microtubules or inhibition of dynein leads to a delay in the maturation of endosomes or the dispersal of late endosomes.

Changes in intraluminal pH

The vacuolar domain of early endosomes contains V-type ATPases in its membrane. These enzymes pump protons from the cytosol into maturing endosomes. A lower intraluminal pH of the maturing endosome provides a better environment for the optimal functioning of the degradative enzymes in the maturing endosome and aids in efficient sorting of internalized molecules.

Changes in protein composition

Upon maturation, the late endosome is enriched with lysosomal hydrolases—proteins with degradative properties. Most of these hydrolases contain inhibitory domains that can inactivate their function. As the maturation progresses, these inhibitory domains are removed. Once the late endosome fuses with the lysosome, these hydrolases can degrade the endocytosed material. Additionally, the late endosome also acquires proteins called SNAREs, as well as some tethering proteins. SNAREs enable maturing endosomes to fuse with each other. Alternatively, they can later fuse with lysosomes and autophagosomes that are formed after phagocytosis.

Suggested Reading


Endosomes Maturation Location Morphology Intraluminal PH Membrane Protein Composition Acidic Late Endosome Multivesicular Body (MVB) Microtubules Dynein Kinesin Motor Proteins Disruption Inhibition Vacuolar Domain V-type ATPases Proton Pumping Degradative Enzymes Sorting Protein Composition Lysosomal Hydrolases

Get cutting-edge science videos from JoVE sent straight to your inbox every month.

Waiting X
Simple Hit Counter