Activating mitotic checkpoint control mechanisms

Abstract

Provided herein are compositions and methods for the treatment of cancer by activating the spindle assembly checkpoint (SAC) in cells. In particular, dimerized Mps1 and Spc105/KNL1 constructs are provided as tunable activators of SAC, allowing for control of chromosome segregation accuracy and prevention of aneuploidies that are common in cancer.

1 . A system comprising:
 (a) an Mps1 polypeptide linked to a first dimerization element; and   (b) a Spc105/KNL1 polypeptide linked to a second dimerization element, wherein dimerization of the first dimerization element and second dimerization element facilitates phosphorylation of the Spc105/KNL1 polypeptide by the Mps1 polypeptide.   
     
     
         2 . The system of  claim 1 , wherein the Mps1 polypeptide comprises a kinase domain having at least 70% sequence similarity with all or a portion of a kinase domain of a wild-type Mps1 protein (SEQ ID NO:2), and retains all or a portion of the kinase activity of the wild-type Mps1 protein. 
     
     
         3 . The system of  claim 2 , wherein the Mps1 polypeptide comprises a kinase domain having at least 70% sequence identity with all or a portion of a kinase domain of a wild-type Mps1 protein (SEQ ID NO:2), and retains all or a portion of the kinase activity of the wild-type Mps1 protein. 
     
     
         4 . The system of  claim 1 , wherein the Spc105/KNL1 polypeptide comprises a phosphodomain having at least 70% sequence similarity with all or a portion of a phosphodomain of a wild-type Spc105 (SEQ ID NO:8) or KNL1 (SEQ ID NO:5) protein, and retains all or a portion of the capacity of the wild-type Spc105 or KNL1 protein to be phosphorylated by Mps. 
     
     
         5 . The system of  claim 2 , wherein the Spc105/KNL1 polypeptide comprises a phosphodomain having at least 70% sequence identity with all or a portion of a phosphodomain of a wild-type Spc105 (SEQ ID NO:8) or KNL1 (SEQ ID NO:5) protein, and retains all or a portion of the capacity of the wild-type Spc105 or KNL1 protein to be phosphorylated by Mps. 
     
     
         6 . The system of  claim 1 , wherein the phosphorylation of the Spc105/KNL1 polypeptide by the Mps1 polypeptide is sufficient to activate a spindle assembly checkpoint (SAC) is a cell within which the phosphorylation occurs. 
     
     
         7 . The system of  claim 1 , wherein the first or second dimerization element is Frb and the other dimerization element is Fkbp12. 
     
     
         8 . The system of  claim 1 , further comprising a dimerization inducer, wherein the dimerization inducer tunably alters the degree of dimerization in a concentration dependent manner. 
     
     
         8 . A composition comprising an Mps1 polypeptide linked to a dimerization element. 
     
     
         9 . The composition of  claim 8 , wherein the Mps1 polypeptide comprises a kinase domain having at least 70% sequence similarity with all or a portion of a kinase domain of a wild-type Mps1 protein (SEQ ID NO:2), and retains all or a portion of the kinase activity of the wild-type Mps1 protein. 
     
     
         10 . The composition of  claim 9 , wherein the Mps1 polypeptide comprises a kinase domain having at least 70% sequence identity with all or a portion of a kinase domain of a wild-type Mps1 protein (SEQ ID NO:2), and retains all or a portion of the kinase activity of the wild-type Mps1 protein. 
     
     
         11 . The composition of  claim 10 , wherein the dimerization element is Frb or Fkbp12. 
     
     
         12 . A composition comprising a Spc105/KNL1 polypeptide linked to a dimerization element. 
     
     
         13 . The composition of  claim 12 , wherein the Spc105/KNL1 polypeptide comprises a phosphodomain having at least 70% sequence similarity with all or a portion of a phosphodomain of a wild-type Spc105 (SEQ ID NO:8) or KNL1 (SEQ ID NO:5) protein, and retains all or a portion of the capacity of the wild-type Spc105 or KNL1 protein to be phosphorylated by Mps. 
     
     
         14 . The composition of  claim 13 , wherein the Spc105/KNL1 polypeptide comprises a phosphodomain having at least 70% sequence identity with all or a portion of a phosphodomain of a wild-type Spc105 or KNL1 protein, and retains all or a portion of the capacity of the wild-type Spc105 (SEQ ID NO:8) or KNL1 (SEQ ID NO:5) protein to be phosphorylated by Mps. 
     
     
         15 . The composition of  claim 14 , wherein the dimerization element is Frb or Fkbp12. 
     
     
         16 . A method of activating a spindle assembly checkpoint (SAC) in a cell comprising administering to the cell a system of  claim 1 . 
     
     
         17 . The method of  claim 16 , wherein activating the SAC prevents aneuploidies in the cell. 
     
     
         18 . The method of  claim 16 , wherein the cell is within a tissue, organ, or subject, and the SAC is activated in all or a group of cells within the tissue, organ, or subject. 
     
     
         19 . The method of  claim 18 , wherein activating the SAC treats or prevents cancer in the cells, tissue, organ, or subject.