Membrane-associated tyrosine- and threonine-specific cdc2-inhibitory kinase (PKMYT1)

Acts as a negative regulator of entry into mitosis (G2 to M transition) by phosphorylation of the CDK1 kinase specifically when CDK1 is complexed to cyclins. Mediates phosphorylation of CDK1 predominantly on 'Thr-14'.

Also involved in Golgi fragmentation. May be involved in phosphorylation of CDK1 on'Tyr-15' to a lesser degree, however tyrosine kinase activity is unclear and may be indirect.