The IQ calmodulin-binding motif is an amino acid sequence motif containing the following sequence: The term "IQ" refers to the first two amino acids of the motif: isoleucine (commonly) and glutamine (invariably).

Calmodulin (CaM) is recognized as a major calcium (Ca2+) sensor and orchestrator of regulatory events through its interaction with a diverse group of cellular proteins.

Three classes of recognition motifs exist for many of the known CaM binding proteins; the IQ motif as a consensus for Ca2+-independent binding and two related motifs for Ca2+-dependent binding, termed 1-14 and 1-5-10 based on the position of conserved hydrophobic residues.

[2] The regulatory domain of scallop myosin is a three-chain protein complex that switches on this motor in response to Ca2+ binding.

Side-chain interactions link the two light chains in tandem to adjacent segments of the heavy chain bearing the IQ-sequence motif.