Previously unknown human cell structure identified.
It is known that cell adhesion is a process by which cells attach to neighbouring cells through specialised structures on their surface. Cell adhesion can occur either through direct contact between cell surfaces or indirect interaction, where cells attach to the extracellular matrix, a gel-like structure containing molecules released by cells into spaces between them. It was assumed that all types of cell adhesion had been identified. Now, a study from researchers led by the Karolinska Institutet discovers a previously unknown structure in human cells. The team state that the structure is a new type of protein complex which the cell uses to attach to its surroundings and which plays a key role in cell division. The study is published in the journal Nature Cell Biology.
Previous studies show that the cells are surrounded by a net-like structure called the extracellular matrix. To attach themselves to the matrix, cells have receptor molecules on their surface which control the assembly of large protein complexes inside them. These so-called adhesion complexes connect the cell exterior to the cell interior and also signal to the cell about its immediate environment, which affects its properties and behaviour. The current study identifies a new type of adhesion complex with a unique molecular composition which sets it apart from those already commonly known.
The current study utilises human cell lines, and uses confocal microscopy and mass spectrometry to identify a previously unknown cell structure they named ‘reticular adhesions’. Results show that the reticular adhesions are a class of adhesion complex which attach to the neighbouring cell and does not dissolve during cell division unlike other types of cell adhesion complexes. Data findings show that the newly discovered structures control the ability of daughter cells to occupy the right place after cell division.
The lab state that the newly discovered adhesion complex can provide answers as to how the cell can remain attached to the matrix during cell division without dissolving to enable division. They go on to add that the previously known adhesion complexes dissolve during the process to allow the cell to divide, whereas this new cell structure does not.
The team surmise they have identified a previously unknown cell structure, a distinct class of cell-matrix adhesion which mediates attachment during cell division. For the future, the researchers state that further research is now needed to examine the new adhesion complex in living organisms.
Source: Karolinska Institutet