Novel functions of plant cyclin-dependent kinase inhibitors, ICK1/KRP1, can act non-cell-autonomously and inhibit entry into mitosis.

Content Provider	Semantic Scholar
Author	Weinl, Christina Marquardt, Sebastian Jakoby, Marc J. Hülskamp, Martin Schnittger, Arp
Copyright Year	2005
Abstract	In animals, cyclin-dependent kinase inhibitors (CKIs) are important regulators of cell cycle progression. Recently, putative CKIs were also identified in plants, and in previous studies, Arabidopsis thaliana plants misexpressing CKIs were found to have reduced endoreplication levels and decreased numbers of cells consistent with a function of CKIs in blocking the G1-S cell cycle transition. Here, we demonstrate that at least one inhibitor from Arabidopsis, ICK1/KRP1, can also block entry into mitosis but allows S-phase progression causing endoreplication. Our data suggest that plant CKIs act in a concentration-dependent manner and have an important function in cell proliferation as well as in cell cycle exit and in turning from a mitotic to an endoreplicating cell cycle mode. Endoreplication is usually associated with terminal differentiation; we observed, however, that cell fate specification proceeded independently from ICK1/KRP1-induced endoreplication. Strikingly, we found that endoreplicated cells were able to reenter mitosis, emphasizing the high degree of flexibility of plant cells during development. Moreover, we show that in contrast with animal CDK inhibitors, ICK1/KRP1 can move between cells. On the one hand, this challenges plant cell cycle control with keeping CKIs locally controlled, and on the other hand this provides a possibility of linking cell cycle control in single cells with the supracellular organization of a tissue or an organ.
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Alternate Webpage(s)	http://pubman.mpdl.mpg.de/pubman/item/escidoc:1222076:1/component/escidoc:1222075/weinl_schnittger_plant_cell_2005.pdf
Alternate Webpage(s)	http://www.plantcell.org/content/17/6/1704.full.pdf
Alternate Webpage(s)	http://www.plantcell.org/content/early/2005/03/04/tpc.104.030486.full.pdf
PubMed reference number	15749764v1
Volume Number	17
Issue Number	6
Journal	The Plant cell
Language	English
Access Restriction	Open
Subject Keyword	Cell Cycle Control Cell Cycle Progression Cell Proliferation Cyclin-Dependent Kinase Inhibitor Proteins Cyclins Endoreduplication Mitosis Plant Cells Specification cell cycle phase transition
Content Type	Text
Resource Type	Article