Why do plants need so many cyclin-dependent kinase inhibitors?
Cell cycle regulation is fundamental to growth and development, and Cyclin-Dependent Kinase Inhibitors (CKIs) are major negative regulators of the cell cycle. Plant genomes encode substantially more CKIs than metazoan or fungal genomes. Plant CKIs fall into 2 distinct families, KIP-RELATED PROTEINS (KRPs) and SIAMESE-RELATED proteins (SMRs). SMRs can inhibit both S-phase and M-phase CDK complexes in vitro and are transcribed throughout the cell cycle, yet SMRs do not inhibit DNA replication in vivo. This suggests that SMRs must be activated post transcriptionally after the start of S-phase, but the mechanism of this hypothesized activation is unknown. Recent work indicates that even distantly related SMRs have the same biochemical function, and that differential transcriptional regulation likely maintains their distinct roles in integrating various environmental and developmental signals with the cell cycle.
a Department of Biological Sciences , Louisiana State University , Baton Rouge , LA , USA.
Narender
N
Kumar
a Department of Biological Sciences , Louisiana State University , Baton Rouge , LA , USA.
John C
JC
Larkin
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002453:Cell Cycle / Q000235:genetics / Q000502:physiology; D050756:Cyclin-Dependent Kinase Inhibitor Proteins / Q000235:genetics / Q000378:metabolism*; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology
D029681:Arabidopsis Proteins; D050756:Cyclin-Dependent Kinase Inhibitor Proteins; D018844:Cyclin-Dependent Kinases
Arabidopsis thaliana; CDK inhibitors; cell cycle; endoreduplication; endoreplication