The role of SNMPs in insect olfaction

Abstract

The sense of smell enables insects to recognize olfactory signals crucial for survival and reproduction. In insects, odorant detection highly depends on the interplay of distinct proteins expressed by specialized olfactory sensory neurons (OSNs) and associated support cells which are housed together in chemosensory units, named sensilla, mainly located on the antenna. Besides odorant-binding proteins (OBPs) and olfactory receptors, so-called sensory neuron membrane proteins (SNMPs) are indicated to play a critical role in the detection of certain odorants. SNMPs are insect-specific membrane proteins initially identified in pheromone-sensitive OSNs of Lepidoptera and are indispensable for a proper detection of pheromones. In the last decades, genome and transcriptome analyses have revealed a wide distribution of SNMP-encoding genes in holometabolous and hemimetabolous insects, with a given species expressing multiple subtypes in distinct cells of the olfactory system. Besides SNMPs having a neuronal expression in subpopulations of OSNs, certain SNMP types were found expressed in OSN-associated support cells suggesting different decisive roles of SNMPs in the peripheral olfactory system. In this review, we will report the state of knowledge of neuronal and non-neuronal members of the SNMP family and discuss their possible functions in insect olfaction.

Coexpression of Three Odorant-Binding Protein Genes in the Foreleg Gustatory Sensilla of Swallowtail Butterfly Visualized by Multicolor FISH Analysis

“…Insects utilize diverse chemical signals for survival, and thus, the study of the chemosensory-related molecules is a fundamental topic in the field of insect science. Recent progress in the next-generation sequencing techniques leads to the comprehensive identification of chemosensory genes in various insects, including "non-model species" (17,27,(48)(49)(50)(51)(52). Because chemosensory organs have many sensilla housing multiple sensory neurons each of which responds to different stimuli in general (35,53,54), investigation of cellular-level expression patterns of chemosensory genes is fundamental for understanding the molecular and neural mechanisms of chemosensation.…”

Latest Developments in Insect Sex Pheromone Research and Its Application in Agricultural Pest Management

“…Genomic and transcriptomic analysis have allowed the identification of new sensory neuron membrane proteins (SNMPs) in Lepidoptera, Diptera, Coleoptera, and Hemiptera (see f.i. the excellent review by Cassau and Krieger [ 94 ]), and their role in pheromone signaling has been noticed [ 95 ]. Very recently, it has been disclosed that a new sensory membrane protein, HarmSNMP1, plays an essential role in the detection of long-chain sex pheromones in Helicoverpa armigera, but this protein was not required for detecting shorter chain sex pheromones of the same species [ 96 ].…”

Transcriptome Profiles of Anopheles Gambiae Harboring Natural Low-Level Plasmodium Infection Reveal Adaptive Advantages For The Mosquito

“…Similarly, while aedine PPKs are hypothesized to function in a variety of sensory modalities, such as chemosensation, hygrosensation and mechanosensation (Matthews et al, 2016), anopheline PPKs remain largely uncharacterized and the implications of these differentially abundant PPKs remain unclear. Sensory neuron membrane proteins (SNMPs) are both colocalized with ORs and broadly expressed throughout D. melanogaster and are postulated to have both chemosensory and non-chemosensory functions (Vogt et al, 2021) with particular roles in dipteran and lepidopteran pheromone detection (Cassau and Krieger, 2020). Both AgSNMP1 and AgSNMP were identified in sequencing libraries, although without significance (Figure 7E).…”