MAST
The microtubule-associated serine/threonine kinase branch of the AGC family comprises MAST1 through MAST4, unusually large enzymes built around a central kinase domain flanked by protein-interaction modules, including a PDZ domain that anchors them at postsynaptic densities and epithelial junctions. MAST2 couples PTEN to PI3K signaling and controls dendritic spine architecture in neurons; inherited loss-of-function variants in MAST1 cause fulminant viral encephalitis by unleashing hyperactive PI3K signaling in immune cells, while MAST4 variants associate with asthma and brain morphology. MAST kinases phosphorylate microtubule- and junction-associated substrates and are regulated in part by AKT-dependent hydrophobic-motif phosphorylation. Their size and domain mosaics make recombinant MAST constructs valuable scaffolding-kinase tools for neurobiology and cancer research.
