ABSTRACT
Mastl (Greatwall) kinase is an essential mitotic protein kinase. Mastl is an atypical member of AGC family with a unique long stretch of non-conserved middle region. The mechanism of its phosphorylation dependent activation has been studied in Xenopus egg extracts, revealing several phosphosites that were suggested to be crucial for kinase activation. These residues correspond to T193 and T206 in the activation loop, and S861 in the C-tail of mouse Mastl. By combining a chemically inducible knockout system to deplete the endogenous Mastl and a viral expression system to ectopically express the mutant variants, we obtained a viable knockout clone that expresses the S861A and S861D mutants. We observed that proliferation rates of the MastlS861A and MastlS861D clones were comparable. Our results have revealed that phosphorylation of the turn motif phosphosite (S861) is auxiliary and it is not indispensable for Mastl function.
Competing Interest Statement
The authors have declared no competing interest.
ABBREVIATIONS
- 4-OHT
- 4-Hydroxytamoxifen;
- DMSO;
- dimethyl sulfoxide;
- HA
- Human influenza hemagglutinin;
- HF
- Hydrophobic Motif;
- MEF
- Mouse Embryonic Fibroblast;
- MUT
- Mutant;
- NCMR
- Non-Conserved Middle Region;
- NLT
- N-Lobe Tether;
- PDB
- The Protein Data Bank;
- SAC
- Spindle Assembly Checkpoint;
- WT
- Wild Type.
