Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland.
Mol Biol Cell. 2021 Apr 15;32(8):703-711. doi: 10.1091/mbc.E20-08-0508. Epub 2021 Feb 24.
The fission yeast cells divide at constant cell size regulated by environmental stimuli. An important pathway of cell size control involves the membrane-associated DYRK-family kinase Pom1, which forms decreasing concentration gradients from cell poles and inhibits mitotic inducers at midcell. Here, we identify the phosphatase 2C Ptc1 as negative regulator of Pom1. Ptc1 localizes to cell poles in a manner dependent on polarity and cell-wall integrity factors. We show that Ptc1 directly binds Pom1 and can dephosphorylate it in vitro but modulates Pom1 localization indirectly upon growth in low-glucose conditions by influencing microtubule stability. Thus, Ptc1 phosphatase plays both direct and indirect roles in the Pom1 cell size control pathway.
裂殖酵母细胞在环境刺激的调控下以恒定的细胞大小进行分裂。细胞大小控制的一个重要途径涉及膜相关的 DYRK 家族激酶 Pom1，它从细胞极形成浓度递减的梯度，并在细胞中部抑制有丝分裂诱导物。在这里，我们确定磷酸酶 2C Ptc1 是 Pom1 的负调控因子。Ptc1 以依赖于极性和细胞壁完整性因素的方式定位于细胞极。我们表明 Ptc1 直接结合 Pom1 并可以在体外对其进行去磷酸化，但在低糖条件下通过影响微管稳定性来间接调节 Pom1 定位。因此，Ptc1 磷酸酶在 Pom1 细胞大小控制途径中发挥直接和间接作用。
