Conserved sequence motifs of olfactory receptor-like proteins may participate in upstream and downstream signal transduction.
Olfactory receptor-like proteins (ORLs) are seven transmembrane domain G protein-coupled receptors. We hypothesize that, in contrast with the hypervariable regions that may interact with a variety of odor ligands, the external and internal segments of the ORLs contain conserved regions that may interact with conserved olfactory binding proteins or direct axon guidance, and with G proteins, respectively. To test this hypothesis, a comprehensive analysis using the multiple expectation maximization for motif elicitation discovery tool was performed in all the full-length ORL clones deposited in the public section of the olfactory receptor database. Ten motifs have been identified that are present in all the olfactory receptors, in the same order, and are not present in other G protein-coupled receptors. These motifs are concentrated either in the extracellular-most or the intracellular-most parts of the receptors. The generality of these motifs was verified by their existence in the partial ORLs and 28 newly identified human receptors. The existence and localization of these motifs, suggest that they may be involved in the interactions of the receptors with their upstream and downstream signaling partners. In addition, the motifs present an additional to overall homology criterion for ORL family definition.
Skoufos
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Yale University School of Medicine, Section of Neurobiology and Center for Medical Informatics, New Haven, CT 06520, USA. skoufos@spine.med.yale.edu
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D016384:Consensus Sequence; D017124:Conserved Sequence; D019204:GTP-Binding Proteins / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D018035:Receptors, Odorant / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction
D018035:Receptors, Odorant; D019204:GTP-Binding Proteins