ERBB2 and breast cancer: In the case of non-client proteins, the loss of Grp94 jeopardizes the plasmalemmal localization of HER-2 receptors in HER-2-expressing breast cancer cells [15] or nNOS docking at the sub-sarcolemma of unloaded skeletal myofibers [7], inducing decreased cell viability and myofiber atrophy, respectively.