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Direct Interaction between Calmodulin and the Grb7 RA-PH Domain

Gabrielle M Watson1, Jacqueline A Wilce1

  • 1Biomedicine Discovery Institute, Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, VIC 3800, Australia.

International Journal of Molecular Sciences
|February 22, 2020
PubMed

Insights

This study demonstrates a direct, calcium-dependent interaction between Grb7 (Growth factor receptor-bound protein 7) and calmodulin (CaM). The binding is mediated by Grb7

Area of Science:

  • Molecular Biology
  • Cell Signaling

Background:

  • Grb7 is a signaling adapter protein involved in cell migration, proliferation, and survival.
  • Grb7's cellular localization is regulated by calmodulin (CaM).
  • A direct interaction between CaM and purified Grb7 has not been previously demonstrated.

Purpose of the Study:

  • To directly demonstrate and quantify the interaction between purified Grb7 and CaM.
  • To identify the specific domain(s) of Grb7 responsible for CaM binding.

Main Methods:

  • Preparation of pure full-length Grb7 and its RA-PH and SH2 subdomains.
  • Surface Plasmon Resonance (SPR) was used to test for CaM binding.

Main Results:

  • A direct, calcium-dependent interaction between full-length Grb7 and CaM was observed.
  • No binding was detected between CaM and the Grb7 SH2 domain alone.
  • A high micromolar affinity interaction was found between the Grb7 RA-PH domain and CaM.

Conclusions:

  • The Grb7-CaM interaction is directly mediated by the Grb7 RA-PH domain.
  • This finding supports a model where CaM binds to Grb7 via its RA-PH region.
Keywords:
CalmodulinGrb7RA-PH domainSH2 domainSPR

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