Department of Biological Chemistry, Center for Cell Dynamics, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA.
Genes Dev. 2011 Apr 1;25(7):730-41. doi: 10.1101/gad.2028611. Epub 2011 Mar 15.
Dynamic assembly and disassembly of actin filaments is a major driving force for cell movements. Border cells in the Drosophila ovary provide a simple and genetically tractable model to study the mechanisms regulating cell migration. To identify new genes that regulate cell movement in vivo, we screened lethal mutations on chromosome 3R for defects in border cell migration and identified two alleles of the gene psidin (psid). In vitro, purified Psid protein bound F-actin and inhibited the interaction of tropomyosin with F-actin. In vivo, psid mutations exhibited genetic interactions with the genes encoding tropomyosin and cofilin. Border cells overexpressing Psid together with GFP-actin exhibited altered protrusion/retraction dynamics. Psid knockdown in cultured S2 cells reduced, and Psid overexpression enhanced, lamellipodial dynamics. Knockdown of the human homolog of Psid reduced the speed and directionality of migration in wounded MCF10A breast epithelial monolayers, whereas overexpression of the protein increased migration speed and altered protrusion dynamics in EGF-stimulated cells. These results indicate that Psid is an actin regulatory protein that plays a conserved role in protrusion dynamics and cell migration.
肌动蛋白丝的动态组装和拆卸是细胞运动的主要驱动力。果蝇卵巢中的边缘细胞为研究调节细胞迁移的机制提供了一个简单且遗传上易于处理的模型。为了鉴定体内调节细胞运动的新基因，我们在 3R 染色体上筛选了致死突变，以寻找边缘细胞迁移缺陷的突变，并鉴定了 psidin（psid）基因的两个等位基因。在体外，纯化的 Psid 蛋白与 F-肌动蛋白结合，并抑制原肌球蛋白与 F-肌动蛋白的相互作用。在体内，psid 突变与编码原肌球蛋白和丝切蛋白的基因表现出遗传相互作用。与 GFP-肌动蛋白共表达 Psid 的边缘细胞表现出突起/缩回动力学的改变。在培养的 S2 细胞中敲低 Psid 减少了，而 Psid 过表达增强了，片状伪足动力学。敲低人 Psid 的同源物降低了 MCF10A 乳腺上皮单层细胞中伤口愈合的迁移速度和方向性，而该蛋白的过表达增加了 EGF 刺激细胞中的迁移速度并改变了突起动力学。这些结果表明，Psid 是一种肌动蛋白调节蛋白，在突起动力学和细胞迁移中发挥保守作用。
