Phosphoregulation of human Mps1 kinase.
The dual-specificity protein kinase Mps1 (monopolar spindle 1) is a phosphoprotein required for error-free mitotic progression in eukaryotes. In the present study, we have investigated human Mps1 phosphorylation using combined mass spectrometric, mutational and phosphospecific antibody approaches. We have identified 16 sites of Mps1 autophosphorylation in vitro, several of which are required for catalytic activity after expression in bacteria or in cultured human cells. Using novel phosphospecific antibodies, we show that endogenous Mps1 is phosphorylated on Thr(686) and Ser(821) during mitosis, and demonstrate that phosphorylated Mps1 localizes to the centrosomes of metaphase cells. Taken together, these results reveal the complexity of Mps1 regulation by multi-site phosphorylation, and demonstrate conclusively that phosphorylated Mps1 associates with centrosomes in mitotic human cells.
Tyler
Rebecca K
RK
Faculty of Life Sciences, University of Manchester, Manchester M139PT, UK.
Chu
Matthew L H
ML
Johnson
Hannah
H
McKenzie
Edward A
EA
Gaskell
Simon J
SJ
Eyers
Patrick A
PA
D000595:Amino Acid Sequence; D020134:Catalytic Domain / Q000235:genetics; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018385:Centrosome / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008938:Mitosis; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017433:Protein Structure, Secondary; D011505:Protein-Tyrosine Kinases; D017386:Sequence Homology, Amino Acid; D053719:Tandem Mass Spectrometry
D018797:Cell Cycle Proteins; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; C075840:TTK protein, human