Hull J Joe, Lee Jae Min, Matsumoto Shogo
Molecular Entomology Laboratory; RIKEN Advanced Science Institute; Wako, Saitama Japan.
Commun Integr Biol. 2010 May;3(3):240-2. doi: 10.4161/cib.3.3.11394.
Store-operated Ca(2+) influx has recently been shown to require the activation of two proteins, stromal interaction molecule 1 (STIM1) and Orai1. In mammals the putative channel ion selectivity filter is thought to comprise conserved charged residues in the first and third transmembrane domains of Orai1 in addition to three residues in the first extracellular loop. The latter residues, however, are not conserved in either of the Bombyx mori Orai1 variants or in most insects, suggesting that selectivity is a relatively recent evolutionary event. In B. mori, thapsigargin-mediated STIM1 redistribution is dependent on a cluster of highly conserved basic residues (amino acids 380-385) in the C terminus that likely interact with acidic residues in the Orai1 C terminus. BmSTIM1 redistribution in vitro also occurs downstream of pheromone biosynthesis activating neuropeptide receptor activation. Activation of in vivo RNA interference mechanisms confirmed the physiological role of BmSTIM1 and Orai1 in sex pheromone production.
近年来研究表明，储存式钙离子内流需要两种蛋白的激活，即基质相互作用分子1（STIM1）和Orai1。在哺乳动物中，推测的通道离子选择性过滤器被认为除了第一细胞外环中的三个残基外，还包括Orai1第一和第三跨膜结构域中的保守带电残基。然而，家蚕的两种Orai1变体以及大多数昆虫中的这些残基都不保守，这表明选择性是一个相对较新的进化事件。在家蚕中，毒胡萝卜素介导的STIM1重新分布依赖于C末端的一组高度保守的碱性残基（氨基酸380 - 385），这些残基可能与Orai1 C末端的酸性残基相互作用。体外BmSTIM1的重新分布也发生在信息素生物合成激活神经肽受体激活的下游。体内RNA干扰机制的激活证实了BmSTIM1和Orai1在性信息素产生中的生理作用。
