PDF(Pubmed)
Abstract：
Microtubules (MTs) are dynamic components of the cytoskeleton and play essential roles in morphogenesis and maintenance of tissue and cell integrity. Despite recent advances in understanding MT ultrastructure, organization, and growth control, how cells regulate MT organization at the cell cortex remains poorly understood. The EFA-6/EFA6 proteins are recently identified membrane-associated proteins that inhibit cortical MT dynamics. Here, combining visualization of endogenously tagged C. elegans EFA-6 with genetic screening, we uncovered tubulin-dependent regulation of EFA-6 patterning. In the mature epidermal epithelium, EFA-6 forms punctate foci in specific regions of the apical cortex, dependent on its intrinsically disordered region (IDR). We further show the EFA-6 IDR is sufficient to form biomolecular condensates in vitro. In screens for mutants with altered GFP::EFA-6 localization, we identified a novel gain-of-function (gf) mutation in an α-tubulin tba-1 that induces ectopic EFA-6 foci in multiple cell types. tba-1(gf) animals exhibit temperature-sensitive embryonic lethality, which is partially suppressed by efa-6(lf), indicating the interaction between tubulins and EFA-6 is important for normal development. TBA-1(gf) shows reduced incorporation into filamentous MTs but has otherwise mild effects on cellular MT organization. The ability of TBA-1(gf) to trigger ectopic EFA-6 foci formation requires β-tubulin TBB-2 and the chaperon EVL-20/Arl2. The tba-1(gf)-induced EFA-6 foci display slower turnover, contain the MT-associated protein TAC-1/TACC, and require the EFA-6 MTED. Our results reveal a novel crosstalk between cellular tubulins and cortical MT regulators in vivo.
摘要：
微管（MT）是细胞骨架的动态组成部分，在组织和细胞完整性的形态发生和维持中起着至关重要的作用。尽管最近在理解MT超微结构方面取得了进展，组织,和生长控制，细胞如何调节细胞皮层的MT组织仍然知之甚少。EFA-6/EFA6蛋白是最近鉴定的抑制皮质MT动力学的膜相关蛋白。这里,将内源性标记的秀丽隐杆线虫EFA-6的可视化与遗传筛选相结合，我们发现了EFA-6模式的微管蛋白依赖性调节。在成熟的表皮上皮中，EFA-6在顶端皮层的特定区域形成点状病灶，依赖于其内在无序区域(IDR)。我们进一步表明EFA-6IDR足以在体外形成生物分子缩合物。在筛选具有改变的GFP::EFA-6定位的突变体时，我们在α-微管蛋白tba-1中发现了一种新的功能获得（gf）突变，该突变在多种细胞类型中诱导异位EFA-6灶。tba-1(gf)动物表现出温度敏感的胚胎致死率，部分被efa-6(lf)抑制，表明微管蛋白和EFA-6之间的相互作用对正常发育很重要。TBA-1（gf）显示出减少的丝状MT的掺入，但对细胞MT组织的影响很小。TBA-1（gf）触发异位EFA-6病灶形成的能力需要β-微管蛋白TBB-2和伴侣EVL-20/Arl2。tba-1(gf)诱导的EFA-6病灶表现出较慢的周转，含有MT相关蛋白TAC-1/TACC，并要求EFA-6MTED。我们的结果揭示了体内细胞微管蛋白和皮质MT调节因子之间的新型串扰。
■MT调节因子EFA-6形成空间限制的点状皮质灶EFA-6N末端内在无序区（IDR）对于体内皮质灶的形成至关重要，并且足以在体外形成液滴。微管蛋白通过EFA-6MT消除域EFA-6灶的形成通过改变TAC和异型更新诱导的TFA-6灶1
■MT调节因子EFA-6形成空间限制的点状皮质灶EFA-6N末端内在无序区（IDR）对于体内皮质灶的形成至关重要，并且足以在体外形成液滴。微管蛋白通过EFA-6MT消除域EFA-6灶的形成通过改变TAC和异型更新诱导的TFA-6灶1
