Protein kinase that seems to act exclusively upon threonine residues (By similarity). Required for normal entry into proliferative arrest after a limited number of cell divisions, also called replicative senescence. Required for normal cell cycle arrest in response to double-stranded DNA damage.
Subcellular locations: Cell projection, Cilium, Cytoplasm
Highest expression in adult heart, followed by pancreas, skeletal muscle, brain, testis, retina, liver, kidney, lung and placenta. Present in most primary carcinomas.