Average G-/F- (Globular-/filamentous-) actin ratio in the lamellipodium of migrating fibroblasts from chick heart

Range of migrating cells 0.22±0.01: of non-migrating cells 0.37±0.01 unitless
Organism Chicken Gallus gallus
Reference Cramer LP, Briggs LJ, Dawe HR. Use of fluorescently labelled deoxyribonuclease I to spatially measure G-actin levels in migrating and non-migrating cells. Cell Motil Cytoskeleton. 2002 Jan51(1):27-38. DOI: 10.1002/cm.10013 p.36 left column bottom paragraphPubMed ID11810694
Method Abstract: "Lamellipodium protrusion is linked to actin filament disassembly in migrating fibroblasts [Cramer, 1999: Curr. Biol. 9:1095-1105]. To further study this relationship, [investigators] have identified a method to specifically and sensitively detect G-actin in distinct spatial locations in motile cells using deoxyribonuclease I (DNase I)."
Comments P.36 left column bottom paragraph: "Spatial Analysis of Actin Levels in Fibroblasts: To compare the relative levels of G- to F-actin in migrating and non-migrating chick fibroblasts, cells were double stained with fluorescently-labelled DNase I and phalloidin (Fig. 5a–d) and the ratio level of G- to F-actin obtained by dividing the G-actin image by the F-actin image (Fig. 5e, f). A low G/F ratio is blue, intermediate G/F ratio is green, and a high G/F ratio is red. Migrating and non-migrating cells were stained and photographed under equivalent conditions. The distribution of actin varied as a function of cell migration. In the lamellipodium, the G/F-actin ratio is lower in migrating cells (Fig.5e, white arrow, blue colour) than in non-migrating cells (Fig. 5f, white arrow, green colour). To quantitate this difference, [investigators] calculated the ratio in individual lamellipodia. The average G-/F-actin ratio in the lamellipodium of migrating cells (0.22±0.01, n=121 cells) is 1.7-fold lower than non-migrating cells (0.37±0.01, n=121 cells). In a Student’s 2-tailed t-test, this is highly significant (P=0.003). In addition, the G/F-actin ratio is significantly reduced in a broad zone immediately behind the lamellipodium, in migrating (Fig. 5e, green, e.g., black arrow) compared with non-migrating cells (Fig. 5f, red, e.g., black arrow). There was no significant difference in the G/F-actin ratio when averaged over the entire cell body, comparing migrating and non-migrating cells."
Entered by Uri M
ID 112787