1WY9

Crystal structure of microglia-specific protein, Iba1

Summary for 1WY9

• Entry DOI: 10.2210/pdb1wy9/pdb
• Descriptor: Allograft inflammatory factor 1, CALCIUM ION (3 entities in total)
• Functional Keywords: ef-hand, calucium binding, metal binding protein
• Biological source: Mus musculus (house mouse)
• Cellular location: Cytoplasm, cytoskeleton: O70200
• Total number of polymer chains: 1
• Total formula weight: 16978.68

Authors

Yamada, M.,Imai, Y.,Kohsaka, S.,Kamitori, S. (deposition date: 2005-02-09, release date: 2006-02-21, Last modification date: 2024-03-13)

Primary citation

Yamada, M.,Ohsawa, K.,Imai, Y.,Kohsaka, S.,Kamitori, S.
X-ray Structures of the Microglia/Macrophage-specific Protein Iba1 from Human and Mouse Demonstrate Novel Molecular Conformation Change Induced by Calcium binding
J.Mol.Biol., 364:449-457, 2006

PubMed Abstract: The ionized calcium-binding adaptor molecule 1 (Iba1) with 147 amino acid residues has been identified as a calcium-binding protein, expressed specifically in microglia/macrophages, and is expected to be a key factor in membrane ruffling, which is a typical feature of activated microglia. We have determined the crystal structure of human Iba1 in a Ca(2+)-free form and mouse Iba1 in a Ca(2+)-bound form, to a resolution of 1.9 A and 2.1 A, respectively. X-ray structures of Iba1 revealed a compact, single-domain protein with two EF-hand motifs, showing similarity in overall topology to partial structures of the classical EF-hand proteins troponin C and calmodulin. In mouse Iba1, the second EF-hand contains a bound Ca(2+), but the first EF-hand does not, which is often the case in S100 proteins, suggesting that Iba1 has S100 protein-like EF-hands. The molecular conformational change induced by Ca(2+)-binding of Iba1 is different from that found in the classical EF-hand proteins and/or S100 proteins, which demonstrates that Iba1 has an unique molecular switching mechanism dependent on Ca(2+)-binding, to interact with target molecules.

PubMed: 17011575
DOI: 10.1016/j.jmb.2006.09.027

Experimental method

X-RAY DIFFRACTION (2.1 Å)