All living organisms are made up of cells. The cell consists of different "compartments" that have different functions. In one of the compartments, the cell nucleus, there is genetic information about how the organism's proteins should look like, and when they should be produced.
The cell nucleus is enclosed by a double lipid membrane that is called the nuclear envelope. All transports in and out of the nucleus take place through pores in the nuclear envelope. It is estimated that there are some 100 different proteins in the nuclear envelope, but today scientists do not yet know precisely how they function.
The protein that the Södertörn researchers have now discovered, called Samp1, normally exists in the membrane envelope that surrounds the cell nucleus. During cell division it turned out that it was part of the process that distributes the chromosomes evenly between the daughter cells, the so-called "mitotic spindle". The protein was therefore named Samp1 (Spindle associated membrane protein 1).
"This discovery was unexpected, since it was previously not believed that integral proteins that are embedded in membranes could be in the mitotic spindle. Nor was it previously understood what functions such proteins would have there," says Professor Hallberg.
The distribution of chromosomes during cell division is extremely rigidly regulated, and the slightest error can lead to the development of tumors. Samp1 will now be a key piece of the puzzle to study in cancer research.
"An integral protein of the inner nuclear membrane localizes to the mitotic spindle in mammalian cells", (Journal of Cell Science 122, 2100-2107), was part of a doctoral thesis at the Karolinska Institutet that was defended at Södertörn University by Dr. Charlotta Buch on February 20 this year.
Einar Hallberg's research team discovered in their study that the Samp1 protein has connections to the cell skeleton outside the cell nucleus. This takes place between cell divisions, when the protein is in the inner membrane of the cell nucleus. It is possible that Samp1 may play an important role when mechanical signals from the outside of the cell are transmitted to the genes in the cell nucleus. Professor Hallberg's research group is now focusing on investigating what role Samp1 might have in the transmission of mechanical signals from the outside of the cell to the genes.
Recently mechanical signaling has been shown to be extremely important in how the body's cells are organized to form various organs. For instance, cultured stem cells develop into nerve cells, muscle cells, or bone cells depending on the stiffness of the material they grow on. Increased knowledge about mechanical signaling is of great importance to stem cell research and future regenerative medicine.Contact: Professor Einar Hallberg, e-mail:email@example.com,
Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden
The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
22.09.2017 | Life Sciences
22.09.2017 | Medical Engineering
22.09.2017 | Physics and Astronomy