  We show that SU(2)_L Yangian and q-deformed SU(2)_R symmetries are realized
in a two-dimensional sigma model defined on a three-dimensional squashed
sphere. These symmetries enable us to develop the two descriptions to describe
its classical dynamics, 1) rational and 2) trigonometric descriptions. The
former 1) is based on the SU(2)_L symmetry and the latter 2) comes from the
broken SU(2)_R symmetry. Each of the Lax pairs constructed in both ways leads
to the same equations of motion. The two descriptions are related one another
through a non-local map.
