FIGURE 6.
Model for Mps1 TPR function. A, Mps1-WT can both dimerize and dock at KTs, thus increasing its local concentration and activity. Mps1 autophosphorylation or phosphorylation of a KT protein allows for its release into the cytoplasm. B, inactive Mps1 can dimerize and localize but cannot phosphorylate itself or other targets and is thus not released from the KT as efficiently as the WT protein. C, Mps1 lacking a functional TPR cannot localize to the KT and cannot dimerize resulting in reduced concentration of Mps1 protein and reduced kinase activity. This is manifest as reduced autophosphorylation and reduced phosphorylation of potential targets. Ultimately this results in suboptimal Mps1 activity.