Lasswell J, Rogg L E, Nelson D C, Rongey C, Bartel B
Department of Biochemistry and Cell Biology, Rice University, Houston, Texas 77005-1892, USA.
Plant Cell. 2000 Dec;12(12):2395-2408. doi: 10.1105/tpc.12.12.2395.
Most indole-3-acetic acid (IAA) in higher plants is conjugated to amino acids, sugars, or peptides, and these conjugates are implicated in regulating the concentration of the free hormone. We identified iar1 as an Arabidopsis mutant that is resistant to the inhibitory effects of several IAA-amino acid conjugates but remains sensitive to free IAA. iar1 partially suppresses phenotypes of a mutant that overproduces IAA, suggesting that IAR1 participates in auxin metabolism or response. We used positional information to clone IAR1, which encodes a novel protein with seven predicted transmembrane domains and several His-rich regions. IAR1 has homologs in other multicellular organisms, including Drosophila, nematodes, and mammals; in addition, the mouse homolog KE4 can functionally substitute for IAR1 in vivo. IAR1 also structurally resembles and has detectable sequence similarity to a family of metal transporters. We discuss several possible roles for IAR1 in auxin homeostasis.
高等植物中的大多数吲哚 - 3 - 乙酸（IAA）与氨基酸、糖类或肽结合，这些结合物参与调节游离激素的浓度。我们将iar1鉴定为拟南芥突变体，它对几种IAA - 氨基酸结合物的抑制作用具有抗性，但对游离IAA仍敏感。iar1部分抑制了过量产生IAA的突变体的表型，表明IAR1参与生长素代谢或响应。我们利用定位信息克隆了IAR1，它编码一种具有七个预测跨膜结构域和几个富含组氨酸区域的新蛋白质。IAR1在包括果蝇、线虫和哺乳动物在内的其他多细胞生物中具有同源物；此外，小鼠同源物KE4在体内可功能性替代IAR1。IAR1在结构上也类似于一类金属转运蛋白家族，并且具有可检测到的序列相似性。我们讨论了IAR1在生长素稳态中的几种可能作用。
