The Na+–H+exchanger-1 induces cytoskeletal changes involving reciprocal RhoA and Rac1 signaling, resulting in motility and invasion in MDA-MB-435 cells

Table 1 Effect of serum deprivation on the kinetic parameters of the allosteric proton regulatory site in human breast cell monolayers

Kinetic parameter	ND	D	D + dn-RhoA	D + dn-Rac1
Vmax	19.6 ± 0.75	26.2 ± 0.86*	31.3 ± 0.88^†	21.6 ± 0.9
K' for H⁺	0.150 ± 0.02	0.113 ± 0.05^†	0.105 ± 0.07^†	0.137 ± 0.023
n_app	2.19	2.16	2.03	2.23

Values are expressed as mean ± standard error for Vmax (mmol/l H⁺/minute) and H⁺ apparent K' (μmol/l) measured at 135 mmol/l external sodium. The Hill coefficient (n_app) was derived at 135 mmol/l external sodium. Confluent cell monolayers were either kept in serum complete medium (nondeprived [ND]) or were placed in serum free growth medium (D) minus or plus dominant negative (dn)-RhoA or dn-Rac1 for 24 hours prior to measurement of ΔH⁺. n = 5; *P < 0.01, ^† P < 0.001, versus ND.

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