biostudies-literatureNovak BBiotechnology and Biological Sciences Research Council2780-2785.e2https://www.ebi.ac.uk/biostudies/studies/S-EPMC9616797biostudies-literatureUnknown32(12)In 1996, Kim Nasmyth¹ proposed that the eukaryotic cell cycle is an alternating sequence of transitions from G₁ to S-G₂-M and back again. These two phases correlate to high activity of cyclin-dependent kinases (CDKs) that trigger S-G₂-M events and CDK antagonists that stabilize G₁ phase. We associated these "alternative phases" with the coexistence of two stable steady states of the biochemical reactions among CDKs and their antagonists.²^,³ Transitions between these steady states (G₁-to-S and M-to-G₁) are driven by "helper" proteins. The fact that the transitions are irreversible is guaranteed by a "latching" property of the molecular switches, as we have argued in previous publicaCurrent biology : CBMitotic kinase oscillation governs the latching of cell cycle switches.PMC9616797BB/M00354X/1Tyson JJNovak BfalseMitotic kinase oscillation governs the latching of cell cycle switches.In 1996, Kim Nasmyth¹ proposed that the eukaryotic cell cycle is an alternating sequence of transitions from G₁ to S-G₂-M and back again. These two phases correlate to high activity of cyclin-dependent kinases (CDKs) that trigger S-G₂-M events and CDK antagonists that stabilize G₁ phase. We associated these "alternative phases" with the coexistence of two stable steady states of the biochemical reactions among CDKs and their antagonists.²^,³ Transitions between these steady states (G₁-to-S and M-to-G₁) are driven by "helper" proteins. The fact that the transitions are irreversible is guaranteed by a "latching" property of the molecular switches, as we have argued in previous publica2022-01-01T00:00:00Z2022 Jun2025-04-19T04:20:19.932Z2025-04-19T04:20:19.932ZS-EPMC96167973550428510.1016/j.cub.2022.04.016