The role of the "sensory neuron membrane protein 1" (SNMP1) in olfactory signal detection in insects

• Applicant: Professor Dr. Jürgen Krieger
• Subject Area: Cognitive, Systems and Behavioural Neurobiology ; Sensory and Behavioural Biology ; Molecular Biology and Physiology of Neurons and Glial Cells
• Term: from 2019 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 415058109

In insects, chemical signals from the surrounding trigger and control various behaviors that are of crucial importance for the survival and the reproductive success. Insects receive relevant volatile chemical signals that are for instance emitted from conspecifics, food sources or oviposition sites by olfactory sensory neurons (OSNs) in the antenna. Studies conducted in holometabolic insects, in particular moth species and Drosophila melanogaster, have demonstrated that the highly sensitive detection of pheromones is achieved by subpopulations of specialized OSNs that are equipped with a specifically tuned odorant receptor (OR) and the CD36-related “sensory neuron membrane protein 1” (SNMP1). SNMP1 is conserved across insect orders and contributes in OSNs expressing pheromone receptors (PRs) to highly sensitive responses as well as to a rapid activation and termination of pheromone-induced reactions. However, the precise role of SNMP1 in the primary processes of pheromone detection as well as its relevance for the sensitive detection of non-pheromonal olfactory signals is unknown. In this respect, our recent analysis of the OR family from the hemimetabolic desert locust, Schistocerca gregaria, revealed that a relatively high number of different OR types is co-expressed with SNMP1, suggesting that SNMP1 not solely operates in pheromone detection but also may play an important role in the sensitive detection of other volatile cues, such as plant-derived volatiles pointing to promising feeding grounds. Before this background, the proposed project aims at illuminating the specific function of SNMP1 in olfactory signal processing and intends to clarify the fundamental question whether SNMP1 is also required for a detection of behaviorally relevant plant-derived odorants. Towards this goal, we will use the desert locust as model and apply various molecular biological, biochemical, electrophysiological and behavioral approaches to investigate the requirement of SNMP1 for the detection of distinct olfactory signals. In addition, we will explore a possible co-receptor function of SNMP1 by analyzing the binding of olfactory relevant ligands to its large extracellular domain. Since olfactory signalling complexes and intracellular transduction pathways may underlie the highly sensitive responses of OSNs to behaviorally relevant olfactory cues, we moreover will scrutinize a role of SNMP1 in triggering metabotropic signalling processes and its possible association with other proteins in an olfactory signaling complex.

• DFG Programme: Research Grants