New insights into the function of a common signal-protein complex

Researchers from Bochum, Düsseldorf and Dortmund have gained new insights into how the Stripak signal-protein complex works. They studied the complex, which occurs in all organisms with a cell nucleus, in the fungus Sordaria ...

A new strategy of cell entry for some types of parvoviruses

Researchers at the Institut national de la recherche scientifique (INRS), in collaboration with American scientists, have discovered a new parvovirus strategy for reaching the cell nucleus, where they reproduce. The results ...

Cells: Divide and enlarge

By far the most important process in cell development is how cells divide and then enlarge in order to multiply.

Unlocking the secrets of plant genomes in high resolution

Resolving genomes, particularly plant genomes, is a very complex and error-prone task. This is because there are several copies of all of the chromosomes and they are very alike. A team of bioinformatics researchers from ...

'Cellular compass' guides stem cell division in plants

The stem cells tasked with creating and maintaining biological tissues have a difficult job. They have to precisely divide to form new specialized cells, which are destined to different fates even though they contain identical ...

How cGAS enzyme is kept bottled up

In higher organisms, detection of DNA in the cytoplasm triggers an immune reaction. The enzyme that senses "misplaced" DNA is also found in the nucleus, but nuclear DNA has no such effect. LMU researchers now report why that ...

Blocking cellular communication stops SARS-CoV-2

In the transmission of signals within the cell which, for example, stimulate cell growth or trigger metabolic processes, phosphate groups play an important biochemical role. The phosphate groups are often attached to proteins ...

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Cell nucleus

In cell biology, the nucleus (pl. nuclei; from Latin nucleus or nuculeus, or kernel), also sometimes referred to as the "control center", is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these chromosomes are the cell's nuclear genome. The function of the nucleus is to maintain the integrity of these genes and to control the activities of the cell by regulating gene expression--the nucleus is therefore the control center of the cell.

The main structures making up the nucleus are the nuclear envelope, a double membrane that encloses the entire organelle and separates its contents from the cellular cytoplasm, and the nuclear lamina, a meshwork within the nucleus that adds mechanical support, much like the cytoskeleton supports the cell as a whole. Because the nuclear membrane is impermeable to most molecules, nuclear pores are required to allow movement of molecules across the envelope. These pores cross both of the membranes, providing a channel that allows free movement of small molecules and ions. The movement of larger molecules such as proteins is carefully controlled, and requires active transport regulated by carrier proteins. Nuclear transport is crucial to cell function, as movement through the pores is required for both gene expression and chromosomal maintenance.

Although the interior of the nucleus does not contain any membrane-bound subcompartments, its contents are not uniform, and a number of subnuclear bodies exist, made up of unique proteins, RNA molecules, and particular parts of the chromosomes. The best known of these is the nucleolus, which is mainly involved in the assembly of ribosomes. After being produced in the nucleolus, ribosomes are exported to the cytoplasm where they translate mRNA.

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