Livanos Pantelis, Kriechbaum Choy, Remers Sophia, Herrmann Arvid, Müller Sabine
Cell Biology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
Center for Plant Molecular Biology, Developmental Genetics, Eberhard Karls Universität Tübingen, Tübingen, Germany.
Nat Commun. 2025 May 14;16(1):4464. doi: 10.1038/s41467-025-58852-w.
Division plane positioning in plants relies on the remarkably accurate selection of the cortical division zone (CDZ), earmarked by the preprophase band of microtubules. The PHRAGMOPLAST ORIENTING KINESIN 1 and 2 (POK1/2) play pivotal roles in CDZ maintenance in mitosis and guide the approaching phragmoplast during cytokinesis. Our knowledge regarding the mechanism of POK recruitment and subsequent maintenance is hitherto limited. Here, we report that POK2 arrives at the preprophase band utilizing a secondary microtubule-binding site within its carboxy-terminus. Effective tethering to the plasma membrane is achieved through non-specific electrostatic interactions with phospholipids. Reaching the cortex via premitotic cortical microtubules emerges as a prerequisite for POK2 polarization, as the order and the density of prophase microtubules become particularly relevant in the preprophase band-compromised mutant trm678. POK2 binding to cortical microtubules templates its future position at the cortex and appears critical for adequate division site setup and consequently tissue architecture.
植物中的分裂平面定位依赖于由微管前中期带标记的皮质分裂区(CDZ)的高度精确选择。成膜体定向驱动蛋白1和2(POK1/2)在有丝分裂期间的CDZ维持中起关键作用,并在胞质分裂期间引导成膜体靠近。迄今为止,我们对POK募集及后续维持机制的了解有限。在此,我们报告POK2利用其羧基末端的一个二级微管结合位点到达前中期带。通过与磷脂的非特异性静电相互作用实现与质膜的有效 tethering(此处原文可能有误,推测为“附着”之类的意思)。通过有丝分裂前的皮质微管到达皮质是POK2极化的先决条件,因为前期微管的顺序和密度在前期带受损的突变体trm678中变得尤为重要。POK2与皮质微管的结合决定了其在皮质的未来位置,并且对于适当的分裂位点设置以及因此的组织结构似乎至关重要。