At each of the irreversible cell-cycle transitions (G1–S, G2–M and M–G1), one of these Cdk regulators is ubiquitinated and subsequently degraded by the proteasome 2.

A 23-year-old amateur boxer died after a charity fight left him with an "irreversible" brain injury, an inquest heard. Jubal Reji Kurian was knocked unconscious and fell backwards from a punch to ...