  Motivated by the ongoing searches for new physics at the LHC, we explore the
low energy consequences of a D-brane inspired $ SU(4)_C\times SU(2)_L \times
SU(2)_R$ (4-2-2) model. The Higgs sector consists of an $SU(4)$ adjoint, a pair
$H+\bar H$ in $(4,1,2)+(\bar 4,1,2)$, and a bidoublet field in $h(1,2,2)$. With
the $SU(4)$ adjoint the symmetry breaks to a left-right symmetric
$SU(3)_C\times U(1)_{B-L} \times SU(2)_L \times SU(2)_R$ model. A missing
partner mechanism protects the $SU(2)_R$ Higgs doublets in $H,\bar H$, which
subsequently break the symmetry to the Standard Model at a few TeV scale. An
inverse seesaw mechanism generates masses for the observed neutrinos and also
yields a sterile neutrino which can play the r\^ole of dark matter if its mass
lies in the keV range. Other phenomenological implications including proton
decay are briefly discussed.
