Commentary

Size control in growing yeast and mammalian cells

Akos Sveiczer¹ , Bela Novak^1,2 and J Murdoch Mitchison³

¹  Department of Agricultural Chemical Technology, Budapest University of Technology and Economics, 1111 Budapest, Szt. Gellert ter 4, Hungary

²  Molecular Network Dynamics Research Group of Hungarian Academy of Sciences, Budapest University of Technology and Economics, 1111 Budapest, Szt. Gellert ter 4, Hungary

³  Institute of Cell, Animal and Population Biology, University of Edinburgh, Ashworth Laboratories, West Mains Rd, Edinburgh EH9 3JT, Scotland, UK

author email corresponding author email

Theoretical Biology and Medical Modelling 2004, 1:12doi:10.1186/1742-4682-1-12

Published:	16 November 2004

Abstract

Background

In a recent publication it was claimed that cultured mammalian cells, in contrast to yeasts, maintain a constant size distribution in the population without a size checkpoint. This inference may be challengeable.

Results

(1) It is argued that "weak" size control implies the existence of a checkpoint, and unfortunately the technique used by Conlon and Raff might obscure such a weak mechanism. (2) Previous investigations of size control in yeasts have shown that individual cell data, rather than means and variances of cell populations, are prerequisites for reliable interpretation. (3) No experimental data so far obtained suggest that in any cell culture a linear growth pattern in cell mass can maintain size homeostasis on its own without size control. (4) Studies on fission yeast mutants indicate that the molecular mechanisms of size control vary with genetic background, implying that no single mechanism is likely to apply to any cell type, including cultured mammalian cells, under all conditions.

Conclusion

The claim that cultured mammalian cells maintain size homeostasis without a checkpoint needs to be re-evaluated by measurements on individual cells.