Laboratory of Biophysics, School of Biological Sciences, and Institute of Microbiology, Seoul National University, Seoul, Republic of Korea.
FEBS Lett. 2011 Jun 23;585(12):1864-72. doi: 10.1016/j.febslet.2011.04.052. Epub 2011 Apr 28.
We investigated the function of homeodomain-containing protein Hbx4 in Dictyostelium discoideum. Hbx4-overexpressing cells (Hbx4(OE)) displayed defects in growth rate and cytokinesis and showed differences in slug motility and cell-type proportioning from KAx3. Furthermore, the overexpression of Hbx4 inhibited the induction of cadA, which encoded the Ca(2+)-dependent cell adhesion molecule DdCAD-1, despite expression of csaA and gpaB. The electrophoretic mobility shift assay showed that the promoter of cadA contained the Hbx4-binding site. Moreover, constitutively expressed DdCAD-1 in Hbx4(OE) rescued the defects in cytokinesis and development. These results suggest that Hbx4 modulates DdCAD-1-mediated cytokinesis and cell-type proportioning.
我们研究了含有同源域的蛋白 Hbx4 在盘基网柄菌中的功能。过表达 Hbx4 的细胞（Hbx4(OE)）在生长速度和胞质分裂方面存在缺陷，与 KAx3 相比，其变形虫运动和细胞类型比例存在差异。此外，尽管 csaA 和 gpaB 表达，但 Hbx4 的过表达抑制了 cadA 的诱导，cadA 编码 Ca(2+)-依赖性细胞粘附分子 DdCAD-1。电泳迁移率变动分析表明，cadA 的启动子含有 Hbx4 结合位点。此外，在 Hbx4(OE)中组成性表达 DdCAD-1 可挽救胞质分裂和发育缺陷。这些结果表明，Hbx4 调节 DdCAD-1 介导的胞质分裂和细胞类型比例。
