Like a Revolving Door: How Shuttling Proteins Operate Nuclear Pores

Shuttling proteins at the nuclear pore – working like a revolving door. Immanuel Wagner/imma.tv

Genetic information is protected in the cell nucleus by a membrane that contains numerous nuclear pores. These pores facilitate the traffic of proteins known as importins that deliver molecular cargoes between the nucleus and the surrounding cytoplasm.

In contrast to prevailing views, the team led by Prof. Roderick Lim, Argovia Professor at the Biozentrum and the Swiss Nanoscience Institute of the University of Basel, has now demonstrated that the nuclear pore complex does not work like a simple filter that regulates the nuclear transport process. Rather, different importins cooperate to continuously open and close the pore like a “revolving door”.

Importins regulate nuclear pores

For a long time scientists have reasoned that a molecular filter within the nuclear pore complex prevents or enables the passage of molecules into the nucleus. Lim’s current study now shows that this filter alone is not sufficient for barrier function but provides only the basic infrastructure for establishing one. Instead, cargo-carrying importins function as bona fide components that regulate the nuclear pore complex transport barrier.

Moreover, Lim and colleagues show how the shuttling of importins is coupled to their barrier function. In fact, importins exist in two interacting forms: alpha and beta. Importin beta promotes cargo access into the pore whereas Importin alpha determines the cargo that can enter the nucleus.

Surprisingly, the team has now discovered that importin alpha acts as a molecular switch that helps to release or retain importin beta to open or close the pore. In the absence of importin alpha, importin beta loses its ability to shuttle through the nuclear pore channel.

Importins in health and disease

The insights provided by the study also have implications for the understanding of diseases associated with transport defects at the nuclear pore complex, such as cancer.

“We always thought of the nuclear pore complex as a standalone machine that controls nuclear transport”, says Lim.

“Now, we have a much greater appreciation for how the systematic interplay of importin alpha and beta are able to regulate the nuclear pore complex to sustain continuous transport. Hence, if importin alpha malfunctions the revolving door mechanism might get stuck such that essential proteins cannot get to their nuclear destinations. Or if importin beta is defective, the pore might become leaky against unwanted substances that can enter and poison the nucleus.”

Original article

Larisa E. Kapinos, Binlu Huang, Chantal Rencurel and Roderick Y.H. Lim
Karyopherins regulate nuclear pore complex barrier and transport function
Journal of Cell Biology (2017), doi: 10.1083/jcb.201702092

Further information

Prof. Dr. Roderick Lim, University of Basel, Biozentrum, and Swiss Nanoscience Institute, Tel. +41 61 207 20 83, E-Mail: roderick.lim@unibas.ch

Heike Sacher, University of Basel, Biozentrum, Communications, Tel. +41 61 207 14 49, email: heike.sacher@unibas.ch

https://www.unibas.ch/en/News-Events/News/Uni-Research/Like-a-Revolving-Door.htm…

Media Contact

Heike Sacher Universität Basel

All latest news from the category: Life Sciences and Chemistry

Articles and reports from the Life Sciences and chemistry area deal with applied and basic research into modern biology, chemistry and human medicine.

Valuable information can be found on a range of life sciences fields including bacteriology, biochemistry, bionics, bioinformatics, biophysics, biotechnology, genetics, geobotany, human biology, marine biology, microbiology, molecular biology, cellular biology, zoology, bioinorganic chemistry, microchemistry and environmental chemistry.

Back to home

Comments (0)

Write a comment

Newest articles

The Sound of the Perfect Coating

Fraunhofer IWS Transfers Laser-based Sound Analysis of Surfaces into Industrial Practice with “LAwave”. Sound waves can reveal surface properties. Parameters such as surface or coating quality of components can be…

Customized silicon chips

…from Saxony for material characterization of printed electronics. How efficient are new materials? Does changing the properties lead to better conductivity? The Fraunhofer Institute for Photonic Microsystems IPMS develops and…

Acetylation: a Time-Keeper of glucocorticoid Sensitivity

Understanding the regulatory mechanism paves the way to enhance the effectiveness of anti-inflammatory therapies and to develop strategies to counteract the negative effects of stress- and age-related cortisol excess. The…

Partners & Sponsors