Cell cycle checkpoint

Steps of the cell cycle. The restriction point occurs between the G1 and S phases of interphase. The G2-M checkpoint occurs between the G2 and M phases. The spindle checkpoint occurs during the M phase. Key cyclins associated with each phase are shown.

Cell cycle checkpoints are control mechanisms in the eukaryotic cell cycle which ensure its proper progression. Each checkpoint serves as a potential termination point along the cell cycle, during which the conditions of the cell are assessed, with progression through the various phases of the cell cycle occurring only when favorable conditions are met. There are many checkpoints in the cell cycle,[1] but the three major ones are: the G1 checkpoint, also known as the Start or restriction checkpoint or Major Checkpoint; the G2/M checkpoint; and the metaphase-to-anaphase transition, also known as the spindle checkpoint.[2] Progression through these checkpoints is largely determined by the activation of cyclin-dependent kinases by regulatory protein subunits called cyclins, different forms of which are produced at each stage of the cell cycle to control the specific events that occur therein.[3][4]

  1. ^ Hartwell, L.; Weinert, T. (3 November 1989). "Checkpoints: controls that ensure the order of cell cycle events". Science. 246 (4930): 629–634. Bibcode:1989Sci...246..629H. doi:10.1126/science.2683079. ISSN 0036-8075. PMID 2683079.
  2. ^ Morgan, David Owen (1958–2007). The cell cycle : principles of control. London: New Science Press. ISBN 978-0-19-920610-0. OCLC 70173205.
  3. ^ Murray, A.; Kirschner, M. (3 November 1989). "Dominoes and clocks: the union of two views of the cell cycle". Science. 246 (4930): 614–621. Bibcode:1989Sci...246..614M. doi:10.1126/science.2683077. ISSN 0036-8075. PMID 2683077.
  4. ^ Morgan, David O. (November 1997). "CYCLIN-DEPENDENT KINASES: Engines, Clocks, and Microprocessors". Annual Review of Cell and Developmental Biology. 13 (1): 261–291. doi:10.1146/annurev.cellbio.13.1.261. ISSN 1081-0706. PMID 9442875.