J. Kondev Colloquium: The Scale Invariant Cell

Dr. Gulliver noticed 150 years ago that the size of the cell's nucleus is proportional to the size of the cell. Other organelles, such as the mitotic spindle, the nucleolus, and mitochondria, also assemble to a size that scales with cell size. These observations lead to a puzzle: How do cells measure their own size and incorporate this information in the process of organelle assembly? I will review experiments that support a simple mechanism for detecting the cell volume, which is based on depleting a pool of building blocks in the process of assembly. In some cases, the cell is faced with the challenge of measuring its length to control the self-assembly of a filamentous structure, in which case the limiting pool mechanism does not work. I will describe some of our recent experiments on yeast cells and related theory that address the question of how cells measure length.