MASTL

Microtubule‐associated serine/threonine kinase like (MASTL), also known as Greatwall (Gwl), is an important mitotic kinase that regulates mitotic progression of normal or transformed cells. The best-characterized substrates of MASTL kinase are cAMP-regulated phosphoprotein 19 (Arpp19) and endosulfine alpha (ENSA, identified due to its high homology with Arpp19), both of which contain the conserved MASTL phosphorylation motif FDSGDY. This kinase function of MASTL has primarily been associated with cell-cycle progression, where it facilitates effective mitotic exit through downregulation of the B55 subunit of protein phosphatase 2A (PP2A). This prevents excessive dephosphorylation by PP2A and mitotic collapse upon nuclear envelope breakdown.