1i2h
CRYSTAL STRUCTURE ANALYSIS OF PSD-ZIP45(HOMER1C/VESL-1L)CONSERVED HOMER 1 DOMAIN
Structural highlights
FunctionHOME1_RAT Postsynaptic density scaffolding protein. Binds and cross-links cytoplasmic regions of GRM1, GRM5, ITPR1, DNM3, RYR1, RYR2, SHANK1 and SHANK3. By physically linking GRM1 and GRM5 with ER-associated ITPR1 receptors, it aids the coupling of surface receptors to intracellular calcium release. May also couple GRM1 to PI3 kinase through its interaction with AGAP2. Differentially regulates the functions of the calcium activated channel ryanodine receptors RYR1 and RYR2. Isoform 1 decreases the activity of RYR2, and increases the activity of RYR1, whereas isoform 3 counteracts the effects by competing for binding sites. Isoform 1 regulates the trafficking and surface expression of GRM5. Isoform 3 acts as a natural dominant negative, in dynamic competition with constitutively expressed isoform 1, and isoform 2 to regulate synaptic metabotropic glutamate function. Isoform 3, may be involved in the structural changes that occur at synapses during long-lasting neuronal plasticity and development.[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedPSD-Zip45 (also named Homer 1c/Vesl-1L) is a synaptic scaffolding protein, which interacts with neurotransmitter receptors and other scaffolding proteins to target them into post-synaptic density (PSD), a specialized protein complex at the synaptic junction. Binding of the PSD-Zip45 to the receptors and scaffolding proteins results in colocalization and clustering of its binding partners in PSD. It has an Ena/VASP homology 1 (EVH1) domain in the N terminus for receptor binding, two leucine zipper motifs in the C terminus for clustering, and a linking region whose function is unclear despite the high level of conservation within the Homer 1 family. The X-ray crystallographic analysis of the largest fragment of residues 1-163, including an EVH1 domain reported here, demonstrates that the EVH1 domain contains an alpha-helix longer than that of the previous models, and that the linking part included in the conserved region of Homer 1 (CRH1) of the PSD-Zip45 interacts with the EVH1 domain of the neighbour CRH1 molecule in the crystal. The results suggest that the EVH1 domain recognizes the PPXXF motif found in the binding partners, and the SPLTP sequence (P-motif) in the linking region of the CRH1. The two types of binding are partly overlapped in the EVH1 domain, implying a mechanism to regulate multimerization of Homer 1 family proteins. Crystal structure of the Homer 1 family conserved region reveals the interaction between the EVH1 domain and own proline-rich motif.,Irie K, Nakatsu T, Mitsuoka K, Miyazawa A, Sobue K, Hiroaki Y, Doi T, Fujiyoshi Y, Kato H J Mol Biol. 2002 May 10;318(4):1117-26. PMID:12054806[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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