Functional Characterization of the Bombyx mori Fatty Acid Transport Protein (BmFATP) within the Silkmoth Pheromone Gland
Functional Characterization of the Bombyx mori Fatty Acid Transport Protein (BmFATP) within the Silkmoth Pheromone Gland
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DOI：
10.1074/jbc.m806072200
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发表时间：
2009-02-20
影响因子：
4.8
通讯作者：
Matsumoto, Shogo
中科院分区：
文献类型：
--
作者：
Ohnishi, Atsushi;Hashimoto, Kana;Matsumoto, Shogo
脂肪酸转运蛋白（FATP）是一种进化上保守的膜结合蛋白，促进细胞外长链脂肪酸的摄取。在人类和小鼠中，已经鉴定出六种FATP亚型，它们的组织特异性分布表明，每种亚型在与脂肪酸摄取相关的脂质代谢中都起着离散的作用。虽然在昆虫中存在FATP同源物已被证实，但它们的功能作用仍有待研究。信息素生成被定义为信息素腺（PG）细胞内生成和组织性信息素生物合成所需的所有机制的动态时期。通过在家蚕PG中利用这一独特系统，我们发现BmFATP主要在PG中表达，并在羽化前1天上调。家蚕PG细胞在羽化前积累了质脂滴（LDs），其作用是以三酰基甘油的形式储存信息素（蚕豆素）前体脂肪酸。rnai介导的BmFATP基因沉默在体内通过阻止三酰基甘油的合成显著抑制LD积累，并导致蚕豆醇产量显著减少。这些结果，结合BmFATP刺激细胞外长链脂肪酸的摄取和BmFATP敲低降低细胞长链酰基-辅酶a合成酶活性的发现，表明BmFATP在蚕豆醇生物合成中发挥重要作用，通过一种称为载体酰化的过程刺激LD积累和三酰基甘油合成，该过程将细胞外脂肪酸的摄取与信息素单一发生过程中辅酶a硫酯的激活结合起来。
Fatty acid transport protein (FATP) is an evolutionarily conserved membrane-bound protein that facilitates the uptake of extracellular long chain fatty acids. In humans and mice, six FATP isoforms have been identified and their tissue-specific distributions suggest that each plays a discrete role in lipid metabolism in association with fatty acid uptake. While the presence of FATP homologs in insects has been demonstrated, their functional role remains to be characterized. Pheromonogenesis is defined as the dynamic period in which all machinery required for sex pheromone biosynthesis is generated and organized within the pheromone gland (PG) cells. By exploiting this unique system in the PG of the silkmoth, Bombyx mori, we found that BmFATP is predominantly expressed in the PG and undergoes up-regulation 1 day prior to eclosion. Before eclosion, B. mori PG cells accumulate cytoplasmic lipid droplets (LDs), which play a role in storing the pheromone (bombykol) precursor fatty acid in the form of triacylglycerol. RNAi-mediated gene silencing of BmFATP in vivo significantly suppressed LD accumulation by preventing the synthesis of triacylglycerols and resulted in a significant reduction in bombykol production. These results, in conjunction with the findings that BmFATP stimulates the uptake of extracellular long-chain fatty acids and BmFATP knockdown reduces cellular long-chain acyl-CoA synthetase activity, suggest that BmFATP plays an essential role in bombykol biosynthesis by stimulating both LD accumulation and triacylglycerol synthesis via a process called vectorial acylation that couples the uptake of extracellular fatty acids with activation to CoA thioesters during pheromonogenesis.