MAST3
MAST3 is the most compact of the four MAST kinases and, together with MAST4, forms the PDZ-less branch of the family: its kinase domain is followed by a coiled-coil segment and a guanylate-kinase-like module rather than the PDZ and microtubule-binding regions carried by MAST1 and MAST2. The protein concentrates at the Golgi apparatus and in the nucleus of cycling cells, with levels that increase through the cell cycle. Its best-characterised substrate is the prolyl isomerase PIN1, whose phosphorylation by MAST3 restrains PIN1 activity and influences mitotic progression. Recombinant MAST3 is used in cell-cycle, Golgi-signalling and kinase-inhibitor selectivity work.
