PDF(Pubmed)
Abstract：
Regulated cell shape change requires the induction of cortical cytoskeletal domains. Often, local changes to plasma membrane (PM) topography are involved. Centrosomes organize cortical domains and can affect PM topography by locally pulling the PM inward. Are these centrosome effects coupled? At the syncytial Drosophila embryo cortex, centrosome-induced actin caps grow into dome-like compartments for mitoses. We found the nascent cap to be a collection of PM folds and tubules formed over the astral centrosomal MT array. The localized infoldings require centrosome and dynein activities, and myosin-based surface tension prevents them elsewhere. Centrosome-engaged PM infoldings become specifically enriched with an Arp2/3 induction pathway. Arp2/3 actin network growth between the infoldings counterbalances centrosomal pulling forces and disperses the folds for actin cap expansion. Abnormal domain topography with either centrosome or Arp2/3 disruption correlates with decreased exocytic vesicle association. Together, our data implicate centrosome-organized PM infoldings in coordinating Arp2/3 network growth and exocytosis for cortical domain assembly.
摘要：
受调节的细胞形状变化需要皮质细胞骨架结构域的诱导。通常,涉及质膜（PM）形貌的局部变化。中心体组织皮质域，并可以通过局部向内拉动PM来影响PM地形。这些中心体效应是耦合的吗？在合胞果蝇胚胎皮层，中心体诱导的肌动蛋白帽长成有丝分裂的圆顶状隔室。我们发现新生帽是在星体中心体MT阵列上形成的PM褶皱和小管的集合。局部折叠需要中心体和动力蛋白活动，和基于肌球蛋白的表面张力阻止他们在其他地方。中心体参与的PM折叠变得特别富含Arp2/3诱导途径。折叠之间的Arp2/3肌动蛋白网络生长抵消了中心体拉力，并分散了肌动蛋白帽扩张的折叠。具有中心体或Arp2/3破坏的异常结构域形貌与减少的外细胞囊泡关联相关。一起,我们的数据表明,中心体组织的PM折叠在协调Arp2/3网络生长和胞吐作用以进行皮质域组装中.
