Genetic evidence for a microtubule-capture mechanism during polarised growth of Aspergillus nidulans
Genetic evidence for a microtubule-capture mechanism during polarised growth of Aspergillus nidulans
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DOI：
10.1242/jcs.169094
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发表时间：
2015-10-01
影响因子：
4
通讯作者：
Fischer, Reinhard
中科院分区：
文献类型：
--
作者：
Manck, Raphael;Ishitsuka, Yuji;Fischer, Reinhard
真核生物细胞从对称性到极性的转换依赖于微管和肌动蛋白骨架。在真菌如裂殖酵母或构巢曲霉中，MT细胞骨架通过皮质细胞末端标记蛋白决定肌动蛋白聚合的位点。在这里，我们描述A。作为丝状真菌中来自酿酒酵母的核融合蛋白Kar9的第一个直系同源物的构巢菌MT指导蛋白A（MigA）。A.构巢菌MigA与皮质ApsA蛋白相互作用，并参与有丝分裂过程中纺锤体的定位。MigA还与隔和核MT组织中心（MTOC）有关。超分辨率光活化定位显微镜（PALM）分析显示，MigA被招募到组装和收回MT加结束在EbA依赖的方式。MigA是菌丝顶端MT收敛所必需的，并且在细胞末端标记物TeaA和TeaR的正确定位中起作用。此外，MigA与V类肌球蛋白相互作用，表明存在一种主动机制来捕获MT并沿沿着肌动蛋白丝拉动末端。因此，MT和肌动蛋白的组织相互依赖，正反馈回路确保了强劲的极性增长。
The cellular switch from symmetry to polarity in eukaryotes depends on the microtubule (MT) and actin cytoskeletons. In fungi such as Schizosaccharomyces pombe or Aspergillus nidulans, the MT cytoskeleton determines the sites of actin polymerization through cortical cell-end marker proteins. Here we describe A. nidulans MT guidance protein A (MigA) as the first ortholog of the karyogamy protein Kar9 from Saccharomyces cerevisiae in filamentous fungi. A. nidulans MigA interacts with the cortical ApsA protein and is involved in spindle positioning during mitosis. MigA is also associated with septal and nuclear MT organizing centers (MTOCs). Super-resolution photoactivated localization microscopy (PALM) analyses revealed that MigA is recruited to assembling and retracting MT plus ends in an EbA-dependent manner. MigA is required for MT convergence in hyphal tips and plays a role in correct localization of the cell-end markers TeaA and TeaR. In addition, MigA interacts with a class-V myosin, suggesting that an active mechanism exists to capture MTs and to pull the ends along actin filaments. Hence, the organization of MTs and actin depend on each other, and positive feedback loops ensure robust polar growth.