Local concentration of G-actin & F-actin in lamellipodia of B16-F1 mouse melanoma cells

Range G-actin ~150μM: F-actin ~500μM μM
Organism Mouse Mus musculus
Reference Koestler, S.A., K. Rottner, F. Lai, J. Block, M. Vinzenz, and J.V. Small. 2009. F- and G-actin concentrations in lamellipodia of moving cells. PLoS ONE. 4:e4810. doi:10.1371/journal.pone.0004810 abstract, p.1 right column 2nd paragraph & p.2 left column 2nd paragraphPubMed ID19277198
Method Abstract: "By comparing fluorescence intensities of bleached and unbleached regions of lamellipodia in B16-F1 mouse melanoma cells expressing EGFP-actin, before and after extraction with Triton X-100, [investigators] show that the ratio of F- to G-actin is 3.2+/-0.9. Using electron microscopy to determine the F-actin content, this ratio translates into F- and G-actin concentrations in lamellipodia of approximately 500 microM and 150 microM, respectively."
Comments P.1 right column 2nd paragraph: "In this work [investigators] established a method to determine the F- and G-actin concentrations in the lamellipodium. [Their] measurements demonstrate a local concentration of G-actin in lamellipodia of around 150 µM, several orders of magnitude higher than the critical concentration for polymerization." P.2 left column 2nd paragraph: "Taking into account some shrinkage during embedding and other published estimates, [investigators] assume here a lamellipodia thickness in B16-F1 cells of 120 nm. Future measurements by cryo electron tomography will lead to a more accurate estimate of this value. Taking this thickness and a density of about 100 filaments/µm at the front of the lamellipodium the concentration of F-actin was estimated as roughly 500 µM (for the calculation see Materials and Methods)."
Entered by Uri M
ID 112791