Somerville Chris
Department of Plant Biology, Carnegie Institution, and Department of Biological Sciences, Stanford University, Stanford, California 94305, USA.
Annu Rev Cell Dev Biol. 2006;22:53-78. doi: 10.1146/annurev.cellbio.22.022206.160206.
Cellulose microfibrils play essential roles in the organization of plant cell walls, thereby allowing a growth habit based on turgor. The fibrils are made by 30 nm diameter plasma membrane complexes composed of approximately 36 subunits representing at least three types of related CESA proteins. The complexes assemble in the Golgi, where they are inactive, and move to the plasma membrane, where they become activated. The complexes move through the plasma membrane during cellulose synthesis in directions that coincide with the orientation of microtubules. Recent, simultaneous, live-cell imaging of cellulose synthase and microtubules indicates that the microtubules exert a direct influence on the orientation of cellulose deposition. Genetic studies in Arabidopsis have identified a number of genes that contribute to the overall process of cellulose synthesis, but the role of these proteins is not yet known.
纤维素微纤丝在植物细胞壁的组织中发挥着重要作用,从而使植物基于膨压形成生长习性。这些微纤丝由直径30纳米的质膜复合体形成,该复合体由约36个亚基组成,这些亚基代表至少三种相关的纤维素合成酶(CESA)蛋白。这些复合体在高尔基体中组装,在那里它们没有活性,然后移动到质膜,在质膜上它们被激活。在纤维素合成过程中,这些复合体沿与微管方向一致的方向穿过质膜。最近,对纤维素合酶和微管的同步活细胞成像表明,微管对纤维素沉积的方向有直接影响。拟南芥的遗传学研究已经鉴定出许多对纤维素合成的整个过程有贡献的基因,但这些蛋白质的作用尚不清楚。