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

Membrane-associated tyrosine- and threonine-specific cdc2-inhibitory kinase (PKMYT1) is a dual-specificity protein kinase that plays a pivotal role in regulating the eukaryotic cell cycle [1]. It specifically targets the Cyclin B-CDK1 complex, phosphorylating CDK1 at the inhibitory residues Threonine-14 and Tyrosine-15 to prevent premature entry into mitosis during the G2 phase [1, 4]. While the related kinase Wee1 primarily phosphorylates Tyr15, PKMYT1 is unique due to its localization to the endoplasmic reticulum and Golgi apparatus and its ability to phosphorylate both sites [1]. In the field of oncology, PKMYT1 has gained prominence as a therapeutic target through the principle of synthetic lethality, especially in cancers with CCNE1 (Cyclin E1) amplification [2]. These cells rely heavily on PKMYT1 to manage the replicative stress caused by Cyclin E1 overexpression; thus, inhibiting PKMYT1 triggers unscheduled CDK1 activation and catastrophic mitotic failure [2, 3]. Clinical candidates such as lunresertib (RP-6306) are currently being evaluated in trials for patients with CCNE1-amplified or FBXW7-mutated solid tumors [3, 5]. This target represents a novel approach to treating DNA damage response-deficient cancers by exploiting specific genetic vulnerabilities [2]. Pharmacological inhibition of PKMYT1 is often combined with other agents to enhance therapeutic efficacy and overcome potential resistance mechanisms [3].

Other names

MYT1Protein kinase membrane-associated tyrosine- and threonine-specific cdc2-inhibitory kinasePKMYT1PPP1R126

Inhibition of PKMYT1 prevents the inhibitory phosphorylation of CDK1, leading to premature mitotic entry and mitotic catastrophe in susceptible cancer cells.