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Conserved sequence repeats of IQGAP1 mediate binding to Ezrin
Jing Liu1, Jesse J Guidry, David K Worthylake
1Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center , 1901 Perdido Street, New Orleans, Louisiana 70112, United States.
Journal of Proteome Research
|December 4, 2013
Summary
The IQGAP1 protein repeats bind to ERM proteins, suggesting IQGAP1 and IQGAP2 are localized to the cell cortex. This interaction may be crucial for cellular signaling pathways.
Area of Science:
- Cell Biology
- Molecular Biology
- Protein Interactions
Background:
- Mammalian IQGAP proteins possess N-terminal repeats of unknown function.
- ERM proteins link the actin cytoskeleton to the cell cortex via their FERM domains.
Purpose of the Study:
- To identify binding partners of the IQGAP1 N-terminal repeats.
- To investigate the interaction between IQGAP1 repeats and ERM proteins.
Main Methods:
- Expression and purification of human IQGAP1 repeats.
- Mass spectrometry to identify protein interactors.
- Isothermal titration calorimetry (ITC) to assess binding kinetics.
Main Results:
- Identified 42 mouse kidney proteins binding to IQGAP1 repeats, including ezrin, radixin, and moesin.
- Direct binding of IQGAP1 repeats to the ezrin FERM domain confirmed by ITC.
- Ezrin FERM domain binds IQGAP2 repeats but not IQGAP3 repeats.
Conclusions:
- IQGAP1 and IQGAP2 are likely recruited to the cell cortex by ERM proteins.
- The IQGAP3 repeats may engage in FERM domain interactions for signaling.
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