How size splits cells
One of the scientists who revealed how plants “do maths” can now reveal how cells take measurements of size. Size is important to cells as it determines when they divide.
In a paper published in eLife, Professor Martin Howard from the John Innes Centre and colleagues from the US, Germany and Singapore discovered that cells measure their surface area using a particular protein, cdr2p. The finding challenges a previous model suggesting that another protein called pom1p senses a cell’s length.
"Many cell types have been shown to reach a size threshold before they commit to cell division and this requires that they somehow monitor their own size," says Professor Martin Howard from the John Innes Centre.
"For the first time we can show how cells sense size and what aspect of size they measure, such as volume, length, mass or surface area."
The scientists found that as cells grow, the concentration of the cdr2p protein grows. The cells use cdr2p to probe the surface area over the whole cell. Their experimental findings contest a previously suggested model.
Fluorescence micrograph showing human cells at various stages of cell division, starting with interphase at the top. During interphase the cell gets bigger and duplicates its DNA. The second cell shows prophase, the stage at which the chromosomes form. The third cell is in metaphase, where all the chromosomes are attached and aligned on the spindle. The fourth cell down shows anaphase, the stage at which the chromosomes separate. The final cell is in telophase, and the newly separated genetic material is encased into two new nuclei.
Credit: Matthew Daniels, Wellcome Images.