Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706.
Plant Cell. 2013 Oct;25(10):3910-25. doi: 10.1105/tpc.113.115162. Epub 2013 Oct 31.
Stomatal cytokinesis defective1 (SCD1) encodes a putative Rab guanine nucleotide exchange factor that functions in membrane trafficking and is required for cytokinesis and cell expansion in Arabidopsis thaliana. Here, we show that the loss of SCD2 function disrupts cytokinesis and cell expansion and impairs fertility, phenotypes similar to those observed for scd1 mutants. Genetic and biochemical analyses showed that SCD1 function is dependent upon SCD2 and that together these proteins are required for plasma membrane internalization. Further specifying the role of these proteins in membrane trafficking, SCD1 and SCD2 proteins were found to be associated with isolated clathrin-coated vesicles and to colocalize with clathrin light chain at putative sites of endocytosis at the plasma membrane. Together, these data suggest that SCD1 and SCD2 function in clathrin-mediated membrane transport, including plasma membrane endocytosis, required for cytokinesis and cell expansion.
气孔胞质分裂缺陷 1（SCD1）编码一种假定的 Rab 鸟嘌呤核苷酸交换因子，它在膜运输中起作用，并且是拟南芥细胞分裂和细胞扩张所必需的。在这里，我们表明 SCD2 功能的丧失会破坏胞质分裂和细胞扩张，并损害生育能力，表型类似于 scd1 突变体观察到的表型。遗传和生化分析表明，SCD1 的功能依赖于 SCD2，并且这些蛋白一起对于质膜内化是必需的。进一步阐明这些蛋白在膜运输中的作用，发现 SCD1 和 SCD2 蛋白与分离的网格蛋白包被小泡相关，并且与质膜上假定的内吞部位的网格蛋白轻链共定位。这些数据表明 SCD1 和 SCD2 参与网格蛋白介导的膜运输，包括质膜内吞作用，这是细胞分裂和细胞扩张所必需的。
