SU(4)_c x SU(2)_L x SU(2)_R model from 5D SUSY SU(4)_c x SU(4)_(L+R)

We investigate supersymmetric $SU(4)_c\times SU(4)_{L+R}$ theory in 5 dimensions whose compactification on a $S^{(1)}/Z_2$ orbifold yields N=1 supersymmetric $SU(4)_c\times SU(2)_L\times SU(2)_R$ supplemented by a $\tl{U}(1)$ gauge symmetry. We discuss how the $\mu $ problem is resolved, a realistic Yukawa sector achieved, and a stable proton realized. Neutrino masses and oscillations are also briefly discussed.