Structural highlights
Function[INAD_DROME] Involved in the negative feedback regulation of the light-activated signaling cascade in photoreceptors through a calcium-mediated process. Interacts with tetrapeptide ligand located in C-terminal sequence of 3 key components of the visual cascade, tethering them and forming a macromolecular signaling phototransduction complex.[1] [2] 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 PubMedIn Drosophila, phototransduction is mediated by G(q)-activation of phospholipase C and is a well studied model system for understanding the kinetics of signal initiation, propagation and termination controlled by G proteins. The proper intracellular targeting and spatial arrangement of most proteins involved in fly phototransduction require the multi-domain scaffolding protein InaD, composed almost entirely of five PDZ domains, which independently bind various proteins including NorpA, the relevant phospho lipase C-beta isozyme. We have determined the crystal structure of the N-terminal PDZ domain of InaD bound to a peptide corresponding to the C-terminus of NorpA to 1.8 A resolution. The structure highlights an intermolecular disulfide bond necessary for high affinity interaction as determined by both in vitro and in vivo studies. Since other proteins also possess similar, cysteine-containing consensus sequences for binding PDZ domains, this disulfide-mediated 'dock-and-lock' interaction of PDZ domains with their ligands may be a relatively ubiquitous mode of coordinating signaling pathways. Functional relevance of the disulfide-linked complex of the N-terminal PDZ domain of InaD with NorpA.,Kimple ME, Siderovski DP, Sondek J EMBO J. 2001 Aug 15;20(16):4414-22. PMID:11500369[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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