Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, SP, Brazil.
Graduate Program in Functional and Molecular Biology, Institute of Biology, University of Campinas, Campinas, SP, Brazil.
Sci Rep. 2017 Mar 7;7:43692. doi: 10.1038/srep43692.
Myosin Va (MyoVa) is an actin-based molecular motor abundantly found at the centrosome. However, the role of MyoVa at this organelle has been elusive due to the lack of evidence on interacting partners or functional data. Herein, we combined yeast two-hybrid screen, biochemical studies and cellular assays to demonstrate that MyoVa interacts with RPGRIP1L, a cilia-centrosomal protein that controls ciliary signaling and positioning. MyoVa binds to the C2 domains of RPGRIP1L via residues located near or in the Rab11a-binding site, a conserved site in the globular tail domain (GTD) from class V myosins. According to proximity ligation assays, MyoVa and RPGRIP1L can interact near the cilium base in ciliated RPE cells. Furthermore, we showed that RPE cells expressing dominant-negative constructs of MyoVa are mostly unciliated, providing the first experimental evidence about a possible link between this molecular motor and cilia-related processes.
肌球蛋白 Va（MyoVa）是一种丰富存在于中心体的基于肌动蛋白的分子马达。然而，由于缺乏相互作用伙伴或功能数据的证据，MyoVa 在这个细胞器中的作用一直难以捉摸。在此，我们结合酵母双杂交筛选、生化研究和细胞测定，证明 MyoVa 与 RPGRIP1L 相互作用，RPGRIP1L 是一种纤毛-中心体蛋白，可控制纤毛信号转导和定位。MyoVa 通过位于 Rab11a 结合位点附近或该位点的残基与 RPGRIP1L 的 C2 结构域结合，Rab11a 结合位点是 V 类肌球蛋白的球形尾部结构域（GTD）中的一个保守位点。根据邻近连接测定，MyoVa 和 RPGRIP1L 可以在纤毛 RPE 细胞的纤毛基部附近相互作用。此外，我们还表明，表达 MyoVa 显性负性构建体的 RPE 细胞大多无纤毛，这为这个分子马达与与纤毛相关的过程之间可能存在的联系提供了第一个实验证据。
