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A Functional Assay for Gap Junctional Examination; Electroporation of Adherent Cells on Indium-Tin Oxide
Published on: October 18, 2014
In vitro GEF and GAP assays
Alexander Eberth1, Mohammad Reza Ahmadian
1Institut für Biochemie und Molekularbiologie II, Klinikum der Heinrich-Heine-Universität, Düsseldorf, Germany.
Current Protocols in Cell Biology
|June 6, 2009
Summary
This study details methods for purifying small GTPases and their regulators, guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). It also outlines techniques for monitoring their nucleotide exchange and hydrolysis activities.
Area of Science:
- Biochemistry
- Molecular Biology
- Cellular Biology
Background:
- Small GTPases are crucial molecular switches regulating cellular functions.
- Their activity depends on GDP/GTP exchange and GTP hydrolysis, catalyzed by GEFs and GAPs.
- Understanding these regulators is key to deciphering cellular signaling pathways.
Purpose of the Study:
- To provide detailed protocols for the expression and purification of small GTPases, GEFs, and GAPs.
- To describe methods for preparing nucleotide-free and fluorescent nucleotide-bound small GTPases.
- To present techniques for monitoring nucleotide exchange and GTP hydrolysis activities.
Main Methods:
- Protein expression and purification of small GTPases and catalytic domains of GEFs/GAPs.
- Preparation of nucleotide-free and fluorescent nucleotide-bound small GTPases.
- Assays for monitoring GEF-catalyzed nucleotide exchange and GAP-stimulated GTP hydrolysis.
Main Results:
- Established protocols for obtaining pure small GTPases, GEFs, and GAPs.
- Developed methods for preparing modified small GTPases for activity assays.
- Validated assays for measuring nucleotide exchange and hydrolysis rates.
Conclusions:
- The described methods enable comprehensive characterization of small GTPase regulatory proteins.
- These techniques facilitate the study of small GTPase function and specificity.
- This work provides a foundation for investigating the biological roles of small GTPases.
