UK scientists have provided fresh insight into the protein-mediated events behind wound healing.

New cells move to plug the gap caused by an injury by attaching to and spreading along a fibronectin protein matrix that exists outside the cells. Martin Humphries and his colleagues at the University of Manchester studied two proteins that mediate the interaction between the cells and the matrix: the integrins and the syndecans.

Integrins and syndecans are found in cell membranes, where they can interact with the cells' external environment. 'Integrins are essential for matrix adhesion, but in some cases are not sufficient for the complete adhesion response,' said Humphries. Although previous work has identified syndecans as major mediators of matrix interaction, he added, whether syndecans are actually required for adhesion has remained 'contentious.'

Humphries explained that his work resolves this question by a precise analysis of the binding. The group attached matrix fragments, called ligands, to glass slides and studied their ability to bind cells. Integrins and syndecans interact with different ligands, but the group found that both ligand types were needed for binding. The two protein types play distinct roles in cell adhesion, said Humphries; integrins alone cannot trigger adhesion, only in combination with syndecans.

'These results help us to understand the molecular mechanisms that cells use to move,' said Humphries. 'Movement is fundamental to a multicellular existence and it also contributes to virtually all human diseases, not just wound healing.' In the next stage of its work, the group hopes to determine how the link between integrins and syndecans controls the direction of cell movement.

Michael Spencelayh