Figure 2.

Insulin signaling controls cell size and number through changes in rates of cell growth and division. (a) Because cell growth and division rates are closely matched in wild-type cells, cell size is kept at a steady state. (b) By reducing cell growth and division rates in parallel, overexpression of dFOXO causes a reduction in cell number but maintains normal cell size. (c) Mutations in chico/IRS1 result in a reduction in both cell number and size, indicating that the rate of cell growth is decreased to a greater extent than the rate of cell division. (d) In dS6K mutants, cell size is reduced but cell number is normal, suggesting a decrease in the rate of cell growth but not cell division.