In animal cells, the coordination of division and growth is obtained by many combinations of the generally occurring mechanisms. Division, as in yeast, is coupled to growth in several animal cell types, such that introduction into a new cell cycle is based on reaching some threshold growth rate or the cell size. Division in other animal cell types does not appear to be based on growth. The size of the cell can be maintained by regular levels of growth factors and mitogens, which act via independent signalling pathways.
