Department of Oral Biology, BK21 PLUS, Yonsei University College of Dentistry, Yonsei-ro 50-1, Seodaemun-gu, Seoul, Korea.
Department of Biological Sciences, Sungkyunkwan University, Suwon, Gyeonggi-do, Korea.
PLoS Genet. 2018 Feb 8;14(2):e1007229. doi: 10.1371/journal.pgen.1007229. eCollection 2018 Feb.
Animals use taste to sample and ingest essential nutrients for survival. Free fatty acids (FAs) are energy-rich nutrients that contribute to various cellular functions. Recent evidence suggests FAs are detected through the gustatory system to promote feeding. In Drosophila, phospholipase C (PLC) signaling in sweet-sensing cells is required for FA detection but other signaling molecules are unknown. Here, we show Gr64e is required for the behavioral and electrophysiological responses to FAs. GR64e and TRPA1 are interchangeable when they act downstream of PLC: TRPA1 can substitute for GR64e in FA but not glycerol sensing, and GR64e can substitute for TRPA1 in aristolochic acid but not N-methylmaleimide sensing. In contrast to its role in FA sensing, GR64e functions as a ligand-gated ion channel for glycerol detection. Our results identify a novel FA transduction molecule and reveal that Drosophila Grs can act via distinct molecular mechanisms depending on context.
动物利用味觉来品尝和摄取生存所需的必需营养素。游离脂肪酸（FAs）是一种富含能量的营养素，有助于各种细胞功能。最近的证据表明，FA 通过味觉系统被检测到，以促进进食。在果蝇中，甜味感应细胞中的 PLC 信号对于 FA 的检测是必需的，但其他信号分子尚不清楚。在这里，我们表明 Gr64e 是对 FA 的行为和电生理反应所必需的。当它们位于 PLC 的下游时，GR64e 和 TRPA1 是可互换的：TRPA1 可以替代 GR64e 在 FA 中，但不能在甘油中，而 GR64e 可以替代 TRPA1 在马兜铃酸中，但不能在 N-甲基马来酰亚胺中。与它在 FA 感应中的作用相反，GR64e 作为甘油检测的配体门控离子通道发挥作用。我们的结果确定了一种新型的 FA 转导分子，并揭示了果蝇 Grs 可以根据上下文通过不同的分子机制发挥作用。
