PROSITE documentation PDOC50096IQ motif profile
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.
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PROSITE method (with tools and information) covered by this documentation:
| 1 | Authors | Cheney R.E. Mooseker M.S. |
| Title | Unconventional myosins. | |
| Source | Curr. Opin. Cell Biol. 4:27-35(1992). | |
| PubMed ID | 1558751 |
| 2 | Authors | Rhoads A.R. Friedberg F. |
| Title | Sequence motifs for calmodulin recognition. | |
| Source | FASEB J. 11:331-340(1997). | |
| PubMed ID | 9141499 |
| 3 | Authors | Baudier J. Deloulme J.C. Van Dorsselaer A. Black D. Matthes H.W.D. |
| Title | Purification 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. | |
| Source | J. Biol. Chem. 266:229-237(1991). | |
| PubMed ID | 1824695 |
| 4 | Authors | Chen S.J. Klann E. Gower M.C. Powell C.M. Sessoms J.S. Sweatt J.D. |
| Title | Studies with synthetic peptide substrates derived from the neuronal protein neurogranin reveal structural determinants of potency and selectivity for protein kinase C. | |
| Source | Biochemistry 32:1032-1039(1993). | |
| PubMed ID | 8424932 |
| 5 | Authors | Xie X. Harrison D.H. Schlichting I. Sweet R.M. Kalabokis V.N. Szent-Gyorgyi A.G. Cohen C. |
| Title | Structure of the regulatory domain of scallop myosin at 2.8 A resolution. | |
| Source | Nature 368:306-312(1994). | |
| PubMed ID | 8127365 | |
| DOI | 10.1038/368306a0 |
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