Control of Cell Growth and Size

我们工作的目标是发现控制细胞生长和大小的基本机制， 真核细胞我们最近的工作集中在两个关键问题上： 1.细胞如何测量和限制生长以控制细胞大小？在所有细胞中，关键的细胞周期转换 只有当足够的生长发生，这确保增殖细胞保持特定的细胞周期， 尺寸因此，细胞必须将生长转化为成比例的信号，当细胞生长时，该信号触发细胞周期进程。 达到一个门槛。细胞测量生长和触发细胞周期转换的机制 一直都是个谜我们最近的研究表明，驱动质膜的囊泡 生长将磷脂酰丝氨酸传递到生长的膜，其募集保守的信号蛋白 以产生与生长程度成比例的信号。此外，我们发现了一个信号 这条通路可以读取生长依赖性信号，并在细胞周期达到 一个门槛生长依赖性信号转导为控制肿瘤细胞的生长提供了一个简单而广泛适用的解决方案。 细胞生长和大小。 2.控制细胞生长和大小的信号是什么？60多年前的观察 指出控制细胞生长和大小之间的密切关系。因此，增长率与 营养的有效性，细胞大小与生长速率成正比，生长速率与细胞大小成正比。 这些关系似乎在所有生命秩序中都存在，这表明它们反映了生命的基本特征。 原则，但基本机制仍然难以捉摸。我们发现， 从保守的TORC2信号网络强制营养之间的比例关系 可用性、细胞生长和细胞大小。例如，我们的工作表明，TORC 2依赖性信号 设定的生长速率也设定了细胞周期进程所需的生长阈值， 将提供一个简单的机械解释之间的比例关系细胞大小和 增速 总之，这些新发现支持了转型假设，可以广泛地解释细胞是如何 生长和大小受到控制。在我们未来的工作中，我们将测试我们的关键假设。 发现，同时还进行了机制分析，以进一步绘制显着的信号网络 控制着细胞的生长和大小我们也将开始把我们在酵母中的发现转化为 了解脊椎动物细胞中细胞生长和大小是如何控制的。

The goal of our work is to discover fundamental mechanisms that control cell growth and size in all eukaryotic cells. Our recent work has focused on two key questions: 1. How do cells measure and limit growth to control cell size? In all cells, key cell cycle transitions occur only when sufficient growth has occurred, which ensures that proliferating cells maintain a specific size. Thus, cells must convert growth to a proportional signal that triggers cell cycle progression when it reaches a threshold. The mechanisms by which cells measure growth and trigger cell cycle transitions have remained deeply mysterious. Our recent work suggests that vesicles that drive plasma membrane growth deliver phosphatidylserine to the growing membrane, which recruits conserved signaling proteins to generate a signal that is proportional to the extent of growth. Furthermore, we discovered a signaling pathway that could read the growth-dependent signal and trigger cell cycle progression when it reaches a threshold. Growth-dependent signaling suggests a simple and broadly applicable solution to control of cell growth and size. 2. What are the signals that control cell growth and size? Observations reaching back over 60 years point to close relationships between control of cell growth and size. Thus, growth rate is proportional to nutrient availability, cell size is proportional to growth rate, and growth rate is proportional to cell size. These relationships appear to hold across all orders of life, which suggest that they reflect fundamental principles, yet the underlying mechanisms have remained elusive. We discovered that signals arising from a conserved TORC2 signaling network enforce proportional relationships between nutrient availability, cell growth, and cell size. For example, our work suggests that TORC2-dependent signals that set growth rate also set the threshold amount of growth required for cell cycle progression, which would provide a simple mechanistic explanation for the proportional relationship between cell size and growth rate. Together, these new discoveries support transformational hypotheses that could broadly explain how cell growth and size are controlled. In our future work, we will test the key hypotheses arising from our discoveries, while also carrying out mechanistic analysis to further map the remarkable signaling networks that control cell growth and size. We will also begin translating our discoveries in yeast into an understanding of how cell growth and size are controlled in vertebrate cells.