Bolduc Nathalie, Hake Sarah, Jackson David
Plant Gene Expression Center, 800 Buchanan Street, Albany, CA 94710, USA.
Sci Signal. 2008 Jun 10;1(23):pe28. doi: 10.1126/scisignal.123pe28.
Homeodomain proteins are well-characterized developmental regulators that control expression of target genes through sequence-specific DNA binding. The homeodomain forms a trihelical structure, with the third helix conferring specific interactions with the DNA major groove. A specific class of plant homeodomain proteins, called KNOX [KNOTTED1 (KN1)-like homeobox], also has the ability to signal between cells by directly trafficking through intercellular channels called plasmodesmata. Trafficking is mediated by a signal that is also contained within the homeodomain. Movement protein binding protein 2C was identified as a protein that interacts with the KN1 homeodomain and regulates the cell-to-cell trafficking of KN1 by sequestering the protein on microtubules. Therefore, KN1 has multiple potential cellular addresses, each of which is conferred by its homeodomain.
同源异型域蛋白是一类特征明确的发育调节因子，它们通过序列特异性DNA结合来控制靶基因的表达。同源异型域形成一种三螺旋结构，其中第三螺旋与DNA大沟形成特异性相互作用。一类特定的植物同源异型域蛋白，称为KNOX [类KNOTTED1 (KN1) 同源异型框]，还具有通过称为胞间连丝的细胞间通道直接运输来在细胞间传递信号的能力。运输由同源异型域中也包含的一种信号介导。运动蛋白结合蛋白2C被鉴定为一种与KN1同源异型域相互作用的蛋白，它通过将该蛋白隔离在微管上来调节KN1的细胞间运输。因此，KN1具有多个潜在的细胞定位，每个定位都由其同源异型域赋予。
