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

Molecular and cellular biochemistry 2012 Dec

filter terms:

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.

Citation

William J Andrews, Conor A Bradley, Elaine Hamilton, Clare Daly, Thérèse Mallon, David J Timson. A calcium-dependent interaction between calmodulin and the calponin homology domain of human IQGAP1. Molecular and cellular biochemistry. 2012 Dec;371(1-2):217-23