Yu F, Morin X, Cai Y, Yang X, Chia W
Institute of Molecular and Cell Biology, National University of Singapore, Singapore.
Cell. 2000 Feb 18;100(4):399-409. doi: 10.1016/s0092-8674(00)80676-5.
Asymmetric localization is a prerequisite for inscuteable (insc) to function in coordinating and mediating asymmetric cell divisions in Drosophila. We show here that Partner of Inscuteable (Pins), a new component of asymmetric divisions, is required for Inscuteable to asymmetrically localize. In the absence of pins, Inscuteable becomes cytoplasmic and asymmetric divisions of neuroblasts and mitotic domain 9 cells show defects reminiscent of insc mutants. Pins colocalizes with Insc and interacts with the region necessary and sufficient for directing its asymmetric localization. Analyses of pins function in neuroblasts reveal two distinct steps for Insc apical cortical localization: A pins-independent, bazooka-dependent initiation step during delamination (interphase) and a later maintenance step during which Baz, Pins, and Insc localization are interdependent.
不对称定位是 inscuteable（insc）在果蝇中协调和介导不对称细胞分裂发挥作用的前提条件。我们在此表明，不对称分裂的新组分——Inscuteable 的伙伴（Pins），是 Inscuteable 进行不对称定位所必需的。在缺乏 pins 的情况下，Inscuteable 会进入细胞质，神经母细胞和有丝分裂结构域 9 细胞的不对称分裂会出现缺陷，这让人联想到 insc 突变体。Pins 与 Insc 共定位，并与指导其不对称定位所必需且充分的区域相互作用。对神经母细胞中 pins 功能的分析揭示了 Insc 顶端皮质定位的两个不同步骤：在脱层（间期）期间，一个独立于 pins、依赖于bazooka 的起始步骤，以及随后的一个维持步骤，在此期间 Baz、Pins 和 Insc 的定位相互依赖。
