The cells of a tissue are surrounded by a network-like structure known as the extracellular matrix. To bind to the matrix, cells have receptor molecules on their surfaces that control the assembly of large complexes of proteins within them.
These so-called adhesion complexes connect the outside to the inside of the cell and also signal to the cell about its immediate environment, which affects its properties and behavior.
Researchers at Karolinska Institutet have now discovered a new type of adhesion complex with a unique molecular composition that sets it apart from those already known. The discovery was made in collaboration with researchers in the UK.
"It is surprising that there is a new cellular structure to discover in 2018," says lead researcher Staffan Strömblad, professor in the Department of Biosciences and Nutrition at Karolinska Institutet. "The existence of this type of adhesion complex has emerged in us."
The newly discovered adhesion complex may provide answers to a still unanswered question - how the cell can remain bound to the matrix during cell division. Previously known adhesion complexes dissolve during the process to allow the cell to divide. But not this new type.
"We show that this new adhesion complex remains and attaches to the cell during cell division," says Professor Strömblad.
The researchers also show that the newly discovered structures control the ability of daughter cells to occupy the right place after cell division. This memory function was disrupted when the researchers blocked the adhesion complex.
The study was performed on human cell lines using mainly confocal microscopy and mass spectrometry. Further research is needed to examine the novel adhesion complex in living organisms.
"Our findings raise many important new questions about the presence and function of these structures," says Professor Strömblad, "We believe they are also involved in processes other than cell division, but this remains to be discovered."
Researchers call the newly discovered cellular structure "reticular adhesions" to reflect its liquid form.[ScienceDaily]