Module 9: Figure CaM redistribution at mitosis
Redistribution of calmodulin during the 90 min time period of mitosis in a HeLa cell.
At the S/G2 interface, calmodulin is concentrated in the nucleus (A), and then begins to segregate into two sites where the centrosomes are located (B and C). As the spindle begins to form, it becomes highly concentrated in the polar regions (D and E), where it remains during metaphase (F), anaphase (G and H) and during cytokinesis (I–P). Towards the end of anaphase, calmodulin begins to concentrate in the cortex immediately below the plasma membrane at the site where the cleavage furrow will form (G). The density in this region builds up progressively at the site where the cleavage processes cut the cell into two. Reproduced from Li, C.J., Heim, R., Lu, P., Tsien, R.Y. and Chang, D.C. (1999) Dynamic redistribution of calmodulin in HeLa cells during cell division as revealed by a GFP–calmodulin fusion protein technique. J. Cell Sci. 112:1567–1577, with permission from The Company of Biologists; see Li et al. 1999.