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Updated: Jul 29, 2026
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Avidity-based Extracellular Interaction Screening (AVEXIS) for the Scalable Detection of Low-affinity Extracellular Receptor-Ligand Interactions
Published on: March 5, 2012
Functional synergy between Rab5 effector Rabaptin-5 and exchange factor Rabex-5 when physically associated in a
R Lippé1, M Miaczynska, V Rybin
1Max Planck Institute for Molecular Cell Biology and Genetics, 01307 Dresden, Germany.
Molecular Biology of the Cell
|July 14, 2001
Summary
The Rabaptin-5 and Rabex-5 complex enhances Rab5 activation and early endosome fusion. This physical association is crucial for efficient endocytic transport and vesicular machinery function.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Rab GTPases regulate vesicular transport.
- Downstream effectors are multiprotein complexes involving nucleotide exchange factors.
- Rab5 controls early endocytic pathway transport.
Purpose of the Study:
- To investigate the functional implications of the Rabex-5/Rabaptin-5 complex formation.
- To determine the necessity of physical association between Rabex-5 and Rabaptin-5 for Rab5-dependent transport.
- To characterize the properties of the reconstituted Rabex-5/Rabaptin-5 complex.
Main Methods:
- Reconstitution of the Rabex-5/Rabaptin-5 complex using recombinant proteins.
- Characterization of the complex's biochemical and functional properties.
- Assays for Rab5 nucleotide exchange activity and endosomal recruitment.
Main Results:
- Rabaptin-5 enhances the Rabex-5 nucleotide exchange activity on Rab5.
- Physical association between Rabex-5 and Rabaptin-5 is essential for Rabaptin-5 recruitment to early endosomes.
- Complex formation is critical for early endosome homotypic fusion.
Conclusions:
- Rabaptin-5 and Rabex-5 exhibit functional synergy within their complex.
- Physical association is necessary for the complex's activity in Rab5-dependent membrane transport.
- Findings have implications for understanding analogous complexes in Rab and Rho GTPase signaling.
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