A Putative Lipophilic Stimulant Carrier Protein Commonly Found in the Taste and Olfactory Systems. A Unique Member of the Pheromone-binding Protein Superfamily

Abstract

In chemosensory systems, a variety of lipophilic ligand-binding proteins have been found in saliva or nasal mucus. Lipophilic stimulants reach the receptor membrane, carried by these proteins. An acidic 14-kDa protein purified in the blowfly, Phormia regina, belongs to the insect pheromone-binding protein superfamily, but unlike other lipohilic ligand-binding proteins in insect or vertebrate chemosensory systems, it was distributed in both taste and olfactory organs. A similar protein was also isolated in Drosophila melanogaster: Considering their distributions, cDNA sequences and structural features, we concluded that these proteins belong to a unique subfamily whose members have convergently evolved for a common function required for both senses of taste and olfaction. By an electrophysiological experiment using antiserum, we also suggested that these proteins carry fragrant components of natural foods in taste systems as well as in olfactory systems.

Soluble proteins in insect chemical communication

“…In other cases, proteins classified as OBPs on the basis of their sequences could in fact be involved in taste. Thus in the fly Phormia regina an OBP, CRLBP, is expressed in taste sensilla of palpi and tarsi, but also in wings and antennae [94,95]. In D. melanogaster and A. gambiae, the expression of OBPs in different organs has been monitored using OBP promoter-driven expression of the LacZ reporter gene [40], in situ hybridisation [41] and reverse transcriptase-polymerase chain reaction (RT-PCR) [44,96,97].…”

Gustatory organs of Drosophila melanogaster : fine structure and expression of the putative odorant-binding protein PBPRP2

“…Unlike its olfactory-specific relatives in Drosophila (McKenna et al 1994;Pikielny et al 1994;Kim et al 1998), PBPRP2 is present not only in the olfactory system, but also in taste organs: labellum, leg, wing, and internal taste organs (Pikielny et al 1994;this study). Another protein of this family has since been found in the gustatory system of the fly Phormia regina, but its subcellular localization is not known (Ozaki et al 1995).…”

“…It was therefore surprising that PBPRP2, a Drosophila member of the OBP family of proteins, is expressed in both olfactory and gustatory organs (Pikielny et al 1994). Subsequently, CRLBPpr, an acidic soluble low-molecular-weight protein, closely related to PBPRP2, was shown to be expressed in the labellar taste sensilla of the blowfly, Phormia regina (Ozaki et al 1995). Yet another soluble lowmolecular-weight protein from the antennae of Carausius morosus, a hemimetabolous insect, is also present in the legs and, hence, may be present in tarsal taste sensilla (Tuccini et al 1996).…”

Identification and Characterization of Two General Odorant Binding Protein Genes from the Oriental Fruit Moth, Grapholita molesta (Busck)

“…OBPs were first discovered in moth antennae (Vogt and Riddiford, 1981), but they have now been identified from various insect orders, such as Lepidoptera (Picimbon et al, 2001;Wang et al, 2003;Xiu and Dong, 2007;Zhang et al, 2011); Diptera (Ozaki et al, 1995;Biessmann et al, 2002;Vogt et al, 2002); Orthoptera (Ban et al, 2003); Coleoptera (Nagnan-Le Meillour et al, 2004); Isoptera (Ishida et al, 2002); Hymenoptera (Calvello et al, 2003;Lu et al, 2007); and Hemiptera (Vogt et al, 1999;Gu et al, 2011). In the Lepidoptera, the odorant-binding proteins are divided into two classes: Pheromone-binding proteins (PBPs) and general odorant binding proteins (GOBPs) (Vogt et al, 1991a,b).…”