Enables cyclin binding activity and cyclin-dependent protein serine/threonine kinase activity. Involved in several processes, including positive regulation of cell size; response to hyperoxia; and response to testosterone. Located in nucleus and perinuclear region of cytoplasm. Biomarker of pancreatic cancer; prostatic hypertrophy; and urinary bladder cancer. Human ortholog(s) of this gene implicated in several diseases, including carcinoma (multiple); familial melanoma; glioblastoma; obesity; and type 2 diabetes mellitus. Orthologous to human CDK4 (cyclin dependent kinase 4). [provided by Alliance of Genome Resources, Apr 2022]