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PROSITE documentation PDOC50096 [for PROSITE entry PS50096]

IQ motif profile





Description

The IQ motif is an extremely basic unit of about 23 amino acids, whose conserved core usually fits the consensus A-x(3)-I-Q-x(2)-F-R-x(4)-K-K. The IQ motif, which can be present in one or more copies, serves as a binding site for different EF-hand proteins (see <PDOC00018>) including the essential and regulatory myosin light chains, calmodulin (CaM), and CaM-like proteins [1,2]. Many IQ motis are protein kinase C (PKC) phosphorylation sites [3,4].

Resolution of the 3D structure of scallop myosin has shown that the IQ motif forms a basic amphipathic helix [5].

Some proteins known to contain an IQ motif are listed below:

  • A number of conventional and unconventional myosins.
  • Neuromodulin (GAP-43) (see <PDOC00344>). This protein is associated with nerve growth. It is a major component of the motile "growth cones" that form the tips of elongating axons.
  • Neurogranin (NG/p17). Acts as a "third messenger" substrate of protein kinase C-mediated molecular cascades during synaptic development and remodeling.
  • Sperm surface protein Sp17.
  • Ras GTPase-activating-like protein IQGAP1. IQGAP1 contains 4 IQ motifs.

The profile we developed covers the entire IQ motif.

Last update:

December 2001 / First entry.

Technical section

PROSITE method (with tools and information) covered by this documentation:

IQ, PS50096; IQ motif profile  (MATRIX)


References

1AuthorsCheney R.E. Mooseker M.S.
TitleUnconventional myosins.
SourceCurr. Opin. Cell Biol. 4:27-35(1992).
PubMed ID1558751

2AuthorsRhoads A.R. Friedberg F.
TitleSequence motifs for calmodulin recognition.
SourceFASEB J. 11:331-340(1997).
PubMed ID9141499

3AuthorsBaudier J. Deloulme J.C. Van Dorsselaer A. Black D. Matthes H.W.D.
TitlePurification and characterization of a brain-specific protein kinase C substrate, neurogranin (p17). Identification of a consensus amino acid sequence between neurogranin and neuromodulin (GAP43) that corresponds to the protein kinase C phosphorylation site and the calmodulin-binding domain.
SourceJ. Biol. Chem. 266:229-237(1991).
PubMed ID1824695

4AuthorsChen S.J. Klann E. Gower M.C. Powell C.M. Sessoms J.S. Sweatt J.D.
TitleStudies with synthetic peptide substrates derived from the neuronal protein neurogranin reveal structural determinants of potency and selectivity for protein kinase C.
SourceBiochemistry 32:1032-1039(1993).
PubMed ID8424932

5AuthorsXie X. Harrison D.H. Schlichting I. Sweet R.M. Kalabokis V.N. Szent-Gyorgyi A.G. Cohen C.
TitleStructure of the regulatory domain of scallop myosin at 2.8 A resolution.
SourceNature 368:306-312(1994).
PubMed ID8127365
DOI10.1038/368306a0



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