A calcium-dependent interaction between calmodulin and the calponin homology domain of human IQGAP1

William J. Andrews, Conor A. Bradley, Elaine Hamilton, Clare Daly, Thérèse Mallon, David J. Timson

Research output: Contribution to journalArticlepeer-review

Abstract

IQGAPs are cytoskeletal scaffolding proteins which collect information from a variety of signalling pathways and pass it on to the microfilaments and microtubules. There is a well-characterised interaction between IQGAP and calmodulin through a series of IQ-motifs towards the middle of the primary sequence. However, it has been shown previously that the calponin homology domain (CHD), located at the N-terminus of the protein, can also interact weakly with calmodulin. Using a recombinant fragment of human IQGAP1 which encompasses the CHD, we have demonstrated that the CHD undergoes a calcium ion-dependent interaction with calmodulin. The CHD can also displace the hydrophobic fluorescent probe 1-anilinonaphthalene-8-sulphonate from calcium-calmodulin, suggesting that the interaction involves non-polar residues on the surface of calmodulin. Molecular modelling identified a possible site on the CHD for calmodulin interaction. The physiological significance of this interaction remains to be discovered.

Original languageEnglish
Pages (from-to)217-223
Number of pages7
JournalMolecular and Cellular Biochemistry
Volume371
Issue number1-2
DOIs
Publication statusPublished - 1 Dec 2012

Keywords

  • ANS displacement assay
  • Calcium-dependent interaction
  • CHD
  • Cytoskeletal scaffolding protein
  • Protein-protein crosslinking

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