Carter Tammy Y, Gadwala Swetha, Chougule Ashish B, Bui Anh P N, Sanders Alex C, Chaerkady Raghothama, Cormier Nathaly, Cole Robert N, Thomas Jeffrey H
Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas.
Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland.
Genesis. 2019 Jun;57(6):e23297. doi: 10.1002/dvg.23297. Epub 2019 Apr 11.
Src64 is required for actomyosin contraction during cellularization of the Drosophila embryonic blastoderm. The mechanism of actomyosin ring constriction is poorly understood even though a number of cytoskeletal regulators have been implicated in the assembly, organization, and contraction of these microfilament rings. How these cytoskeletal processes are regulated during development is even less well understood. To investigate the role of Src64 as an upstream regulator of actomyosin contraction, we conducted a proteomics screen to identify proteins whose expression levels are controlled by src64. Global levels of actin are reduced in src64 mutant embryos. Furthermore, we show that reduction of the actin isoform Actin 5C causes defects in actomyosin contraction during cellularization similar to those caused by src64 mutation, indicating that a relatively high level of Actin 5C is required for normal actomyosin contraction and furrow canal structure. However, reduction of Actin 5C levels only slows down actomyosin ring constriction rather than preventing it, suggesting that src64 acts not only to modulate actin levels, but also to regulate the actomyosin cytoskeleton by other means.
Src64在果蝇胚胎胚盘细胞化过程中的肌动球蛋白收缩中是必需的。尽管许多细胞骨架调节因子与这些微丝环的组装、组织和收缩有关，但肌动球蛋白环收缩的机制仍知之甚少。这些细胞骨架过程在发育过程中是如何被调控的，人们了解得更少。为了研究Src64作为肌动球蛋白收缩上游调节因子的作用，我们进行了一项蛋白质组学筛选，以鉴定其表达水平受src64控制的蛋白质。在src64突变体胚胎中，肌动蛋白的整体水平降低。此外，我们表明，肌动蛋白异构体肌动蛋白5C水平的降低会导致细胞化过程中肌动球蛋白收缩出现缺陷，类似于src64突变所导致的缺陷，这表明正常的肌动球蛋白收缩和沟道结构需要相对较高水平的肌动蛋白5C。然而，肌动蛋白5C水平的降低只会减缓肌动球蛋白环的收缩，而不会阻止它，这表明src64不仅作用于调节肌动蛋白水平，还通过其他方式调节肌动球蛋白细胞骨架。
