Sechi Stefano, Frappaolo Anna, Fraschini Roberta, Capalbo Luisa, Gottardo Marco, Belloni Giorgio, Glover David M, Wainman Alan, Giansanti Maria Grazia
Istituto di Biologia e Patologia Molecolari del CNR, Dipartimento di Biologia e Biotecnologie, Università Sapienza di Roma, Piazzale A. Moro 5, 00185 Roma, Italy.
Dipartimento di Biotecnologie e Bioscienze, Università degli studi di Milano Bicocca, Piazza della Scienza 2, 20126 Milan, Italy.
Open Biol. 2017 Jan;7(1). doi: 10.1098/rsob.160257.
Cytokinesis requires a tight coordination between actomyosin ring constriction and new membrane addition along the ingressing cleavage furrow. However, the molecular mechanisms underlying vesicle trafficking to the equatorial site and how this process is coupled with the dynamics of the contractile apparatus are poorly defined. Here we provide evidence for the requirement of Rab1 during cleavage furrow ingression in cytokinesis. We demonstrate that the gene omelette (omt) encodes the Drosophila orthologue of human Rab1 and is required for successful cytokinesis in both mitotic and meiotic dividing cells of Drosophila melanogaster We show that Rab1 protein colocalizes with the conserved oligomeric Golgi (COG) complex Cog7 subunit and the phosphatidylinositol 4-phosphate effector GOLPH3 at the Golgi stacks. Analysis by transmission electron microscopy and 3D-SIM super-resolution microscopy reveals loss of normal Golgi architecture in omt mutant spermatocytes indicating a role for Rab1 in Golgi formation. In dividing cells, Rab1 enables stabilization and contraction of actomyosin rings. We further demonstrate that GTP-bound Rab1 directly interacts with GOLPH3 and controls its localization at the Golgi and at the cleavage site. We propose that Rab1, by associating with GOLPH3, controls membrane trafficking and contractile ring constriction during cytokinesis.
胞质分裂需要肌动球蛋白环收缩与沿着正在内陷的分裂沟添加新膜之间紧密协调。然而，囊泡运输到赤道部位的分子机制以及该过程如何与收缩装置的动力学相耦合，目前还不清楚。在这里，我们提供了在胞质分裂中分裂沟内陷期间Rab1需求的证据。我们证明基因煎蛋卷（omt）编码人类Rab1的果蝇直系同源物，并且在黑腹果蝇的有丝分裂和减数分裂细胞中成功进行胞质分裂是必需的。我们表明Rab1蛋白与高尔基体堆叠处的保守寡聚高尔基体（COG）复合体Cog7亚基和磷脂酰肌醇4-磷酸效应器GOLPH3共定位。通过透射电子显微镜和3D-SIM超分辨率显微镜分析发现，omt突变体精母细胞中正常的高尔基体结构丧失，这表明Rab1在高尔基体形成中起作用。在分裂细胞中，Rab1能使肌动球蛋白环稳定并收缩。我们进一步证明，结合GTP的Rab1直接与GOLPH3相互作用，并控制其在高尔基体和分裂位点的定位。我们提出，Rab1通过与GOLPH3结合，在胞质分裂过程中控制膜运输和收缩环收缩。
