  We review the dynamical generation of coupling constants in 4D supergravity
by means of gauge three-form fields. The latter are introduced as components of
particular chiral supermultiplets and can be coupled to membranes preserving
local supersymmetry. Such a set-up naturally arises from type-II string
compactifications on Calabi-Yau manifolds with fluxes. We present generic 4D
$\mathcal N=1$ supergravity models with three-form multiplets and study domain
wall solutions supported by membranes, which interpolate between vacua with
different values of the cosmological constant.
