Dynamics of Cell Growth and Division, Institut de Biologie Cellulaire et de Génétique, Centre National de la Recherche Scientifique, UMR 5095, 33000 Bordeaux, France.
J Cell Biol. 2013 Feb 18;200(4):407-18. doi: 10.1083/jcb.201206081. Epub 2013 Feb 11.
Formation of a stable polarity axis underlies numerous biological processes. Here, using high-resolution imaging and complementary mathematical modeling we find that cell polarity can be established via the spatial coordination of opposing membrane trafficking activities: endocytosis and exocytosis. During polarity establishment in budding yeast, these antagonistic processes become apposed. Endocytic vesicles corral a central exocytic zone, tightening it to a vertex that establishes the polarity axis for the ensuing cell cycle. Concomitantly, the endocytic system reaches an equilibrium where internalization events occur at a constant frequency. Endocytic mutants that failed to initiate periodic internalization events within the corral displayed wide, unstable polarity axes. These results, predicted by in silico modeling and verified by high resolution in vivo studies, identify a requirement for endocytic corralling during robust polarity establishment.
稳定的极性轴的形成是许多生物过程的基础。在这里，我们使用高分辨率成像和互补的数学建模发现，细胞极性可以通过相反的膜运输活动的空间协调来建立：内吞作用和外排作用。在出芽酵母的极性建立过程中，这些拮抗过程会靠拢。内吞小泡包围一个中央外排区，将其收紧成一个顶点，为随后的细胞周期建立极性轴。同时，内吞系统达到平衡，内化事件以恒定的频率发生。在围栏内未能启动周期性内化事件的内吞突变体显示出宽而不稳定的极性轴。这些结果由计算机建模预测，并通过高分辨率体内研究验证，确定了在强大的极性建立过程中内吞作用的重要性。
