ABSTRACT
In mammals, circadian rhythms are generated by delayed negative feedback, in which period (PER1–PER3) and cryptochrome (CRY1, CRY2) proteins gradually accumulate in the nucleus to suppress the transcription of their own genes. Although the importance of nuclear import and export signals for the subcellular localization of clock proteins is well established, little is known about the dynamics of these processes as well as their importance for the generation of circadian rhythms. We show by pharmacological perturbations of oscillating cells that nuclear import and export are of crucial importance for the circadian period. Live-cell fluorescence microscopy revealed that nuclear import of the key circadian protein PER2 is fast and further accelerated by CRY1. Moreover, PER2 nuclear import is crucially dependent on a specific nuclear-receptor-binding motif in PER2 that also mediates nuclear immobility. Nuclear export, however, is relatively slow, supporting a model of PER2 nuclear accumulation by rapid import, slow export and substantial nuclear degradation.
Footnotes
Competing interests
The authors declare no competing interests.
Author contributions
R.Ö., S.K., B.K. and A.K. designed and performed the experiments; T.K. and A.H. provided technical and conceptual support; R.Ö., S.K., B.K., T.K., A.H. and A.K. analyzed the data; A.K., R.Ö. and S.K. wrote the manuscript.
Funding
This work was supported by the German Research Foundation [grant numbers SFB740/C3 to A.H. and SFB740/D2 to A.K].
Supplementary material available online at http://jcs.biologists.org/lookup/suppl/doi:10.1242/jcs.156612/-/DC1
- Received May 15, 2014.
- Accepted July 13, 2014.
- © 2014. Published by The Company of Biologists Ltd
Article navigation
Related articles
Cited by...
More in this TOC section
Similar articles
Subject collections
Other journals from The Company of Biologists
First Person interviews
Have you seen our First Person interviews with the early-career first authors of our papers? The authors talk about their work in and out of the lab, the journeys that led them to where they are now and the scientists who inspired them along the way. Recently, we caught up with first authors Maitreyi Rathod, Sushmita Chatterjee, Lotte Vanheer, Rachel Furlong, Pamela Adami, Ruiqi Wang and Chen Yu.
Travelling Fellowship – New imaging approach unveils a bigger picture
Find out how Pamela Imperadore’s Travelling Fellowship grant from The Company of Biologists took her to Germany, where she used new imaging techniques to investigate the cellular machinery underlying octopus arm regeneration. Don’t miss the next application deadline for 2020 travel, coming up on 29 November. Where will your research take you?
preLights – Meet the preLighters: an interview with Maiko Kitaoka
Maiko Kitaoka is a graduate student in the lab of Rebecca Heald at the University of California, Berkeley. Here she studies the cause of chromosome mis-segregation defects in Xenopus hybrids. We caught up with Maiko to discuss her research, science communication, ballet, preprints and more.
Journal Meeting – Cell Dynamics: Host-Pathogen Interface
Registration is now open for the third instalment of the highly successful Cellular Dynamics Meeting Series, and will focus on ‘Host-Pathogen Interface’. The meeting will take place 17-20 May 2020, and further information is available here.
Cell Science at a Glance – Adaptor protein complexes and disease at a glance
A new poster from the Robinson lab summarises what is known about the five adaptor protein complexes and discuss how this helps to explain the clinical features of different genetic disorders.
JCS joins the Review Commons initiative
Journal of Cell Science is pleased to be a part of the new and exciting Review Commons initiative, launched by EMBO and ASAPbio. Streamlining the publishing process, Review Commons enables high-quality peer review to take place before journal submission. Papers submitted to Review Commons will be assessed independently of any journal, focusing solely on the paper’s scientific rigor and merit.
Articles of interest in our sister journals
Casein kinase 1α decreases β-catenin levels at adherens junctions to facilitate wound closure in Drosophila larvae
Chang-Ru Tsai, Michael J. Galko
Development
Spherical spindle shape promotes perpendicular cortical orientation by preventing isometric cortical pulling on both spindle poles during C. elegans female meiosis
Elizabeth Vargas, Karen P. McNally, Daniel B. Cortes, Michelle T. Panzica, Brennan M. Danlasky, Qianyan Li, Amy Shaub Maddox, Francis J. McNally
Development