A new structure present in human cells has been observed by Swedish and British scientists. This structure is described as a new type of protein complex that the cell uses to attach itself to its environment and proves to play a key role in cell division. It has been named reticular adhesion to reflect its net shape.
The cells that make up a tissue are surrounded by a net-like structure called an extracellular matrix. To bind to the matrix, the cells have on their surface receptor molecules that control the assembly of large protein complexes inside. These so-called adhesion complexes connect the outside to the inside of the cell and also allow the cell to know its immediate environment, which modifies its properties and behavior.
Professor Staffan Strömblad and his colleagues at the Karolinska Institute at the University of Manchester have identified a new type of adhesion complex whose unique molecular composition distinguishes it from those already known.
“It is incredibly surprising that there is still a new cell structure to discover in 2018. The existence of this type of adhesion complex has completely overwhelmed us,” explains Strömblad .
According to the researchers, the newly discovered adhesion complex could help to understand how the cell remains attached to the matrix during cell division. To date, known adhesion complexes dissolve during the process to allow the cell to divide. Now, this one does not dissolve.
We have shown that this new adhesion complex remains and fixes the cell during cell division.
Researchers have also shown that the newly discovered structures control the ability of daughter cells to take the right place after cell division. This ability was interrupted when scientists blocked the newly discovered adhesion complex.
This breakthrough has been achieved on human cell lines mainly through confocal microscopy, which allows images of very shallow depth of field (about 400 nm), and mass spectrometry, which can be used to detect and identify molecules from their mass.
Scientists now want to do other work that will examine the new adhesion complex in living organisms. “Our findings raise several questions about the presence and functioning of these structures. We believe that they are also involved in processes other than cell division, but this remains to be discovered,” says Staffan Strömblad.
The study is published in the journal Nature Cell Biology.