Related Experiment Video
Updated: May 24, 2026

Investigating Mast Cell Secretory Granules; from Biosynthesis to Exocytosis
Published on: January 26, 2015
Regulation of endocytosis by the small GTP-ase Rab5
1European Molecular Biology Laboratory, Meyerhofstrasse 1, Postfach 10.2209, D-6900, Heidelberg, Germany.
Abstract:
Rab5 is a small GTPase associated with the plasma membrane and the early endosomes. Expression of wild type rab5 and a mutant protein defective in GTP-binding in BHK cells led to alterations in the rate of endocytosis and in the morphology of endocytic organelles. The results obtained suggest that rab5 is a rate limiting GTPase that regulate the kinetics of both lateral fusion of early endosomes and fusion of plasma membrane-derived endocytic vesicles with early endosomes.
Related Concept Videos
Rab Cascades
Rab Proteins
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
Recycling Endosomes and Transcytosis
The recycling endosome is not a single organelle but an extensively tubulated network of recycling pathways. It functions in storing molecules or transporting them across...
The Early Endosome: Endocytosis of Transferrin
Small GTPases - Ras and Rho
Three regulatory proteins control their activity:
GTPases and their Regulation
Large G-proteins, also known...

