Figure 2

Role of Na⁺–H⁺ exchanger (NHE)1 in serum deprivation-dependent rearrangement of the actin cytoskeleton. (a) To examine the role of NHE1 in serum deprivation-induced reorganization of the actin cytoskeleton underlying motility and invasive ability, MDA-MB-435 cell monolayers were left in fresh whole growth medium (nondeprived [ND]) or were serum deprived (D) in the presence or absence of 2 μmol/l of the specific NHE1 inhibitor 5-(N, N-dimethyl)-amiloride (DMA) for 1 day. The fluorescent photomicrographs show cell groups at a magnification of 40× (bar = 10 μm). (b) typical one-parameter fluorescence distributions of MDA-MB-435 cells labelled with phalloidin–fluorescein isothiocyanate in the above experimental conditions. The lighter coloured curve is from control, ND cells. Cyt B is the fluorescence distribution after treatment with the actin cytoskeleton disruptor cytochalasin B (5 μmol/l for 15 min). (c) Relative intracellular F-actin content measured by flow cytometry in MDA-MB-435 cells in the above experimental conditions. Mean ± standard error. n = 9; **P < 0.001 versus ND cells.