IQGAP proteins IQGAP1, IQGAP2 and IQGAP3 possess IQ repeats (isoleucine- and glutamine-rich motifs) that bind CALM1 (calmodulin) in the presence of calcium ions (Atcheson et al. 2011, Andrews et al. 2012). IQGAP1 also binds the calmodulin-related proteins myosin essential light chain (MLCS1A) and S100B (Atcheson et al. 2011). Calmodulin binding inhibits the association of IQGAPs with the F-actin (Bashour et al. 1997, Pelikan-Conchaudron et al. 2011).