AK6 (adenylate kinase 6) is a nuclear-localized phosphotransferase that catalyzes reversible phosphoryl transfer between nucleoside triphosphates and monophosphates, with broad substrate specificity and intrinsic ATPase activity. Beyond canonical nucleotide metabolism, AK6 plays a specialized role in ribosomal maturation: its ATPase activity (but not NMP activity) is required for late cytoplasmic maturation of 40S ribosomal subunits, specifically 18S rRNA maturation, through transient association with ribosomal protein uS11. AK6 may also regulate Cajal body formation and contribute to nuclear energy homeostasis. In testicular carcinoma cells, AK6 regulates WNK1 phosphorylation and ion homeostasis; knockdown inhibits proliferation and promotes apoptosis 1. A 2021 review documents AK6 dysfunction in cancer and inflammatory diseases, linking it to carcinogenesis and tumor progression 2. Recent evidence from a Drosophila neurodegeneration screen implicates glial adenosine metabolism—controlled partly through AK6—as a therapeutic target in Parkinson's disease, with AK6 knockdown improving locomotor function and rescuing dopaminergic neurodegeneration 3. In asthenospermia patients, AK6 expression is significantly reduced; coordinated inhibition of AK1, AK6, and AK7 markedly decreases sperm motility 4, suggesting a role in male fertility.