CDK inhibitors, p21Cip1 and p27Kip1, participate in cell cycle exit of mammalian cardiomyocytes

Shoji Tane, Aiko Ikenishi, Hitomi Okayama, Noriko Iwamoto, Keiichi I. Nakayama, Takashi Takeuchi

Research output: Contribution to journalArticlepeer-review

48 Citations (Scopus)


Mammalian cardiomyocytes actively proliferate during embryonic stages, following which cardiomyocytes exit their cell cycle after birth. The irreversible cell cycle exit inhibits cardiac regeneration by the proliferation of pre-existing cardiomyocytes. Exactly how the cell cycle exit occurs remains largely unknown. Previously, we showed that cyclin E- and cyclin A-CDK activities are inhibited before the CDKs levels decrease in postnatal stages. This result suggests that factors such as CDK inhibitors (CKIs) inhibit CDK activities, and contribute to the cell cycle exit. In the present study, we focused on a Cip/Kip family, which can inhibit cyclin E- and cyclin A-CDK activities. Expression of p21Cip1 and p27Kip1 but not p57Kip2 showed a peak around postnatal day 5, when cyclin E- and cyclin A-CDK activities start to decrease. p21Cip1 and p27 Kip1 bound to cyclin E, cyclin A and CDK2 at postnatal stages. Cell cycle distribution patterns of postnatal cardiomyocytes in p21Cip1 and p27Kip1 knockout mice showed failure in the cell cycle exit at G1-phase, and endoreplication. These results indicate that p21Cip1 and p27Kip play important roles in the cell cycle exit of postnatal cardiomyocytes.

Original languageEnglish
Pages (from-to)1105-1109
Number of pages5
JournalBiochemical and Biophysical Research Communications
Issue number3
Publication statusPublished - Jan 17 2014

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


Dive into the research topics of 'CDK inhibitors, p21<sup>Cip1</sup> and p27<sup>Kip1</sup>, participate in cell cycle exit of mammalian cardiomyocytes'. Together they form a unique fingerprint.

Cite this