Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
Science. 2011 Aug 26;333(6046):1141-4. doi: 10.1126/science.1205727.
Cell-to-cell communication in plants includes the selective trafficking of transcription factors and other signals through plasmodesmata. The KNOTTED1 (KN1) homeobox (KNOX) family transcription factors, which use this pathway, are essential for stem cell establishment and/or maintenance. Here we show that KN1 trafficking requires the chaperonin complex, which belongs to a group of cytosolic chaperones that fold specific substrate proteins. Genetic and physical interaction data show a functional relevance for chaperonins in KNOX family-dependent stem cell maintenance. Furthermore, tissue-specific complementation assays indicate a mechanistic basis for chaperonin function during the posttranslocational refolding process. Our study shows that chaperonins are essential for the cell-to-cell trafficking of a subset of mobile transcription factors and demonstrates the importance of chaperonin-dependent protein trafficking for plant stem cell function.
植物细胞间通讯包括通过胞间连丝选择性运输转录因子和其他信号。使用这种途径的 KNOTTED1（KN1）同源盒（KNOX）家族转录因子对于干细胞的建立和/或维持是必不可少的。在这里，我们表明 KN1 的运输需要分子伴侣复合物，该复合物属于一组细胞溶质伴侣，可折叠特定的底物蛋白。遗传和物理相互作用数据表明，分子伴侣在 KNOX 家族依赖性干细胞维持中具有功能相关性。此外，组织特异性互补测定表明，在翻译后重折叠过程中，分子伴侣的功能具有机制基础。我们的研究表明，分子伴侣对于一组可移动转录因子的细胞间运输是必不可少的，并证明了分子伴侣依赖性蛋白质运输对于植物干细胞功能的重要性。
