Editing Cell cycle (section)

===Cyclin-dependent kinase and cyclin evolution===
Cell-cycle progression is controlled by the oscillating concentrations of different [[cyclin]]s and the resulting molecular interactions from the various [[cyclin-dependent kinase]]s (CDKs). In yeast, just one CDK (Cdc28 in ''[[Saccharomyces cerevisiae|S. cerevisiae]]'' and Cdc2 in ''[[Schizosaccharomyces pombe|S. pombe]]'') controls the cell cycle.<ref>{{cite journal | vauthors = Morgan DO | title = Cyclin-dependent kinases: engines, clocks, and microprocessors | journal = Annual Review of Cell and Developmental Biology | volume = 13 | issue = 1 | pages = 261–291 | date = November 1997 | pmid = 9442875 | doi = 10.1146/annurev.cellbio.13.1.261 }}</ref> However, in animals, whole families of CDKs have evolved.<ref>{{cite journal | vauthors = Malumbres M, Harlow E, Hunt T, Hunter T, Lahti JM, Manning G, Morgan DO, Tsai LH, Wolgemuth DJ | display-authors = 6 | title = Cyclin-dependent kinases: a family portrait | journal = Nature Cell Biology | volume = 11 | issue = 11 | pages = 1275–1276 | date = November 2009 | pmid = 19884882 | pmc = 2914104 | doi = 10.1038/ncb1109-1275 }}</ref><ref>{{cite journal | vauthors = Satyanarayana A, Kaldis P | title = Mammalian cell-cycle regulation: several Cdks, numerous cyclins and diverse compensatory mechanisms | journal = Oncogene | volume = 28 | issue = 33 | pages = 2925–2939 | date = August 2009 | pmid = 19561645 | doi = 10.1038/onc.2009.170 | s2cid = 3096776 }}</ref> Cdk1 controls entry to mitosis and Cdk2, Cdk4, and Cdk6 regulate entry into S phase. Despite the evolution of the CDK family in animals, these proteins have related or redundant functions.<ref>{{cite journal | vauthors = Barrière C, Santamaría D, Cerqueira A, Galán J, Martín A, Ortega S, Malumbres M, Dubus P, Barbacid M | display-authors = 6 | title = Mice thrive without Cdk4 and Cdk2 | journal = Molecular Oncology | volume = 1 | issue = 1 | pages = 72–83 | date = June 2007 | pmid = 19383288 | pmc = 5543859 | doi = 10.1016/j.molonc.2007.03.001 }}</ref><ref>{{cite journal | vauthors = Ortega S, Prieto I, Odajima J, Martín A, Dubus P, Sotillo R, Barbero JL, Malumbres M, Barbacid M | display-authors = 6 | title = Cyclin-dependent kinase 2 is essential for meiosis but not for mitotic cell division in mice | journal = Nature Genetics | volume = 35 | issue = 1 | pages = 25–31 | date = September 2003 | pmid = 12923533 | doi = 10.1038/ng1232 | s2cid = 19522248 }}</ref><ref>{{cite journal | vauthors = Aleem E, Kiyokawa H, Kaldis P | title = Cdc2-cyclin E complexes regulate the G1/S phase transition | journal = Nature Cell Biology | volume = 7 | issue = 8 | pages = 831–836 | date = August 2005 | pmid = 16007079 | doi = 10.1038/ncb1284 | s2cid = 10842071 }}</ref> For example, ''cdk2 cdk4 cdk6'' triple knockout mice cells can still progress through the basic cell cycle.<ref name=":3">{{cite journal | vauthors = Santamaría D, Barrière C, Cerqueira A, Hunt S, Tardy C, Newton K, Cáceres JF, Dubus P, Malumbres M, Barbacid M | display-authors = 6 | title = Cdk1 is sufficient to drive the mammalian cell cycle | journal = Nature | volume = 448 | issue = 7155 | pages = 811–815 | date = August 2007 | pmid = 17700700 | doi = 10.1038/nature06046 | s2cid = 4412772 | bibcode = 2007Natur.448..811S }}</ref> ''cdk1'' knockouts are lethal, which suggests an ancestral CDK1-type kinase ultimately controlling the cell cycle.<ref name=":3" />

''[[Arabidopsis thaliana]]'' has a Cdk1 homolog called CDKA;1, however ''cdka;1'' ''A. thaliana'' mutants are still viable,<ref>{{cite journal | vauthors = Nowack MK, Harashima H, Dissmeyer N, Zhao X, Bouyer D, Weimer AK, De Winter F, Yang F, Schnittger A | display-authors = 6 | title = Genetic framework of cyclin-dependent kinase function in Arabidopsis | journal = Developmental Cell | volume = 22 | issue = 5 | pages = 1030–1040 | date = May 2012 | pmid = 22595674 | doi = 10.1016/j.devcel.2012.02.015 | doi-access = free }}</ref> running counter to the [[opisthokont]] pattern of CDK1-type kinases as essential regulators controlling the cell cycle.<ref name=":4">{{cite journal | vauthors = Harashima H, Dissmeyer N, Schnittger A | title = Cell cycle control across the eukaryotic kingdom | journal = Trends in Cell Biology | volume = 23 | issue = 7 | pages = 345–356 | date = July 2013 | pmid = 23566594 | doi = 10.1016/j.tcb.2013.03.002 }}</ref> Plants also have a unique group of B-type CDKs, whose functions may range from development-specific functions to major players in mitotic regulation.<ref>{{cite journal | vauthors = Boudolf V, Barrôco R, Engler J, Verkest A, Beeckman T, Naudts M, Inzé D, De Veylder L | display-authors = 6 | title = B1-type cyclin-dependent kinases are essential for the formation of stomatal complexes in Arabidopsis thaliana | journal = The Plant Cell | volume = 16 | issue = 4 | pages = 945–955 | date = April 2004 | pmid = 15031414 | doi = 10.1105/tpc.021774 | pmc = 412868 | doi-access = free | bibcode = 2004PlanC..16..945B }}</ref><ref>{{cite journal | vauthors = Andersen SU, Buechel S, Zhao Z, Ljung K, Novák O, Busch W, Schuster C, Lohmann JU | display-authors = 6 | title = Requirement of B2-type cyclin-dependent kinases for meristem integrity in Arabidopsis thaliana | journal = The Plant Cell | volume = 20 | issue = 1 | pages = 88–100 | date = January 2008 | pmid = 18223038 | pmc = 2254925 | doi = 10.1105/tpc.107.054676 | bibcode = 2008PlanC..20...88A }}</ref>