title: Pom1 and cell size homeostasis in fission yeast.
abstract: Cells sense their size and use this information to coordinate cell division with cell growth to maintain a constant cell size within a given population. A model has been proposed for cell size control in the rod-shaped cells of the fission yeast, Schizosaccharomyces pombe. This involves a protein localized to the cell ends, which inhibits mitotic activators in the middle of the cell in a cell size-dependent manner. This protein, Pom1, along with another tip-localized protein, Nif1, have been implicated as direct sensors of cell size controlling the onset of mitosis. Here we have investigated cell size variability and size homeostasis at the G 2/M transition, focusing on the role of pom1 and nif1. Cells deleted for either of these 2 genes show wild-type size homeostasis both in size variability analyses and size homeostasis experiments. This indicates that these genes do not have a critical role as direct cell size sensors in the control mechanism. Cell size homeostasis also seems to be independent of Cdc2-Tyr15 phosphorylation, suggesting that the size sensing mechanism in fission yeast may act through an unidentified pathway regulating CDK activity by an unknown mechanism.
authors.affiliation: Cell Cycle Laboratory Cancer Research UK London Research Institute; London, UK.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Wood
authors.forename: Paul
authors.initials: P
authors.lastname: Nurse
mesh_terms: D016203:CDC2 Protein Kinase / Q000378:metabolism; D002455:Cell Division; D048429:Cell Size; D016195:G2 Phase; D006706:Homeostasis; D046210:Microfluidic Analytical Techniques; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: C105626:NIF1 protein, S pombe; D012097:Repressor Proteins; D029702:Schizosaccharomyces pombe Proteins; D011494:Protein Kinases; C112212:Pom1 protein, S pombe; D016203:CDC2 Protein Kinase; C469447:cdc2 protein, S pombe
keywords: Pom1; cell cycle; cell size control; cell size variability; fission yeast; growth rate
references.citation: J Cell Sci. 1996 Dec;109 ( Pt 12):2947-57
references.pmid: 9013342
references.citation: Yeast. 1998 Jul;14(10):943-51
references.pmid: 9717240
references.citation: Methods Enzymol. 1991;194:795-823
references.pmid: 2005825
references.citation: J Cell Sci. 2004 Oct 15;117(Pt 22):5293-302
references.pmid: 15454577
references.citation: J Cell Sci. 1977 Apr;24:51-67
references.pmid: 893551
references.citation: Genome Biol. 2012 May 24;13(5):R36
references.pmid: 22624651
references.citation: Exp Cell Res. 1965 Oct;40(1):12-20
references.pmid: 5838935
references.citation: Exp Cell Res. 1971 Aug;67(2):368-74
references.pmid: 4255493
references.citation: Nat Cell Biol. 2007 Nov;9(11):1263-72
references.pmid: 17952063
references.citation: Nature. 1968 Sep 7;219(5158):1077-9
references.pmid: 4876941
references.citation: J Cell Sci. 1985 Apr;75:357-76
references.pmid: 4044680
references.citation: Exp Cell Res. 1965 May;38:272-84
references.pmid: 14284508
references.citation: Nature. 2009 Jun 11;459(7248):857-60
references.pmid: 19474789
references.citation: Nature. 1990 Apr 5;344(6266):503-8
references.pmid: 2138713
references.citation: Biol Rev Camb Philos Soc. 2001 Feb;76(1):65-101
references.pmid: 11325054
references.citation: Curr Biol. 2004 Dec 14;14(23):R1014-27
references.pmid: 15589139
references.citation: Nature. 2005 May 26;435(7041):507-12
references.pmid: 15917811
references.citation: Nature. 1989 Nov 2;342(6245):39-45
references.pmid: 2682257
references.citation: J Cell Sci. 2006 Nov 15;119(Pt 22):4710-8
references.pmid: 17077120
references.citation: Nature. 1975 Aug 14;256(5518):547-51
references.pmid: 1165770
references.citation: Exp Cell Res. 1977 Jul;107(2):365-75
references.pmid: 872890
references.citation: Nature. 2009 Jun 11;459(7248):852-6
references.pmid: 19474792
references.citation: Genes Dev. 1998 May 1;12(9):1356-70
references.pmid: 9573052
references.citation: Exp Cell Res. 1977 Jul;107(2):377-86
references.pmid: 872891
references.citation: Exp Cell Res. 1978 Sep;115(2):317-29
references.pmid: 689088
references.citation: BMC Biol. 2012 Dec 14;10:101
references.pmid: 23241366
references.citation: Nature. 2010 Dec 23;468(7327):1074-9
references.pmid: 21179163
references.citation: Cell. 1987 May 22;49(4):559-67
references.pmid: 3032459
references.citation: Cell. 1986 Apr 11;45(1):145-53
references.pmid: 3955656
references.citation: Curr Biol. 2006 Dec 19;16(24):2480-7
references.pmid: 17140794
references.citation: Nature. 1981 Aug 6;292(5823):558-60
references.pmid: 7254352
references.citation: J Gen Microbiol. 1962 Nov;29:421-34
references.pmid: 13976593
references.citation: Curr Biol. 2012 May 8;22(9):R350-9
references.pmid: 22575477
references.citation: EMBO J. 1996 Feb 15;15(4):839-49
references.pmid: 8631305
references.citation: EMBO J. 1997 Mar 17;16(6):1342-50
references.pmid: 9135149
references.citation: Cell. 2011 Jun 24;145(7):1116-28
references.pmid: 21703453
references.citation: Cell. 1991 Mar 22;64(6):1111-22
references.pmid: 1706223