Benton Richard, Vannice Kirsten S, Vosshall Leslie B
Laboratory of Neurogenetics and Behaviour, The Rockefeller University, 1230 York Avenue, Box 63, New York, New York 10065, USA.
Nature. 2007 Nov 8;450(7167):289-93. doi: 10.1038/nature06328. Epub 2007 Oct 17.
The CD36 family of transmembrane receptors is present across metazoans and has been implicated biochemically in lipid binding and transport. Several CD36 proteins function in the immune system as scavenger receptors for bacterial pathogens and seem to act as cofactors for Toll-like receptors by facilitating recognition of bacterially derived lipids. Here we show that a Drosophila melanogaster CD36 homologue, Sensory neuron membrane protein (SNMP), is expressed in a population of olfactory sensory neurons (OSNs) implicated in pheromone detection. SNMP is essential for the electrophysiological responses of OSNs expressing the receptor OR67d to (Z)-11-octadecenyl acetate (cis-vaccenyl acetate, cVA), a volatile male-specific fatty-acid-derived pheromone that regulates sexual and social aggregation behaviours. SNMP is also required for the activation of the moth pheromone receptor HR13 by its lipid-derived pheromone ligand (Z)-11-hexadecenal, but is dispensable for the responses of the conventional odorant receptor OR22a to its short hydrocarbon fruit ester ligands. Finally, we show that SNMP is required for responses of OR67d to cVA when ectopically expressed in OSNs not normally activated by pheromones. Because mammalian CD36 binds fatty acids, we suggest that SNMP acts in concert with odorant receptors to capture pheromone molecules on the surface of olfactory dendrites. Our work identifies an unanticipated cofactor for odorant receptors that is likely to have a widespread role in insect pheromone detection. Moreover, these results define a unifying model for CD36 function, coupling recognition of lipid-based extracellular ligands to signalling receptors in both pheromonal communication and pathogen recognition through the innate immune system.
跨膜受体CD36家族存在于后生动物中，在生物化学上与脂质结合和运输有关。几种CD36蛋白在免疫系统中作为细菌病原体的清道夫受体发挥作用，并且似乎通过促进对细菌衍生脂质的识别而充当Toll样受体的辅助因子。在这里，我们表明果蝇的CD36同源物，感觉神经元膜蛋白（SNMP），在一群与信息素检测有关的嗅觉感觉神经元（OSN）中表达。SNMP对于表达受体OR67d的OSN对（Z）-11-十八碳烯基乙酸酯（顺式- vaccenyl acetate，cVA）的电生理反应至关重要，cVA是一种挥发性的雄性特异性脂肪酸衍生信息素，可调节性和社会聚集行为。SNMP对于蛾类信息素受体HR13被其脂质衍生的信息素配体（Z）-11-十六碳烯醛激活也是必需的，但对于传统气味受体OR22a对其短烃类水果酯配体的反应则是可有可无的。最后，我们表明，当在通常不被信息素激活的OSN中异位表达时，SNMP对于OR67d对cVA的反应是必需的。因为哺乳动物的CD36结合脂肪酸，我们认为SNMP与气味受体协同作用，在嗅觉树突表面捕获信息素分子。我们的工作确定了一种气味受体的意外辅助因子，它可能在昆虫信息素检测中具有广泛作用。此外，这些结果定义了一个统一的CD36功能模型，将基于脂质的细胞外配体的识别与信息素通讯和通过先天免疫系统的病原体识别中的信号受体耦合起来。
