Arabidopsis KRPs have distinct inhibitory activity toward cyclin D2‐associated kinases, including plant‐specific B‐type cyclin‐dependent kinase

Abstract

Arabidopsis contains seven Kip‐related protein (KRP) genes encoding CDK (cyclin‐dependent kinase) inhibitors (CKIs), which shares a restricted similarity with mammalian p27^Kip1. Here, we analyze the characteristics of the KRPs. Although KRP1–KRP7 interact with active cyclin D2 (CYCD2)/CDKA and CYCD2/CDKB complexes to a similar extent, they inhibit kinase activity to a different extent. Our results suggest that inhibitory activity is related to the binding ability between KRP proteins and cyclin/CDK complexes, but secondary and tertiary structure may be also involved. These data provide the first evidence that KRPs inhibit kinase activity associated with plant‐specific CDKB.