Report

Teaser, summary, work performed and final results

Periodic Reporting for period 2 - MAIN (Molecular Adhesion and Interactions in the Nervous system)

Teaser

Interactions and communication between cells in our body is important for the function and formation of tissues. Cells interact to provide mechanic support and shape organs, and cells exchange signals in order to function coherently. Disruption of these processes can lead to...

Summary

Interactions and communication between cells in our body is important for the function and formation of tissues. Cells interact to provide mechanic support and shape organs, and cells exchange signals in order to function coherently. Disruption of these processes can lead to pathologies ranging from cancer to developmental disorders. The interaction and communication between cells is for a large part organized by proteins expressed on cell surfaces. On the cell surface these proteins can act as receptors or as ligands to receive or send signals from one cell to the other. In addition, these proteins can interact between cells and form adhesion complexes to shape our organs. It is not well understood how cell-surface expressed proteins organize themselves to control intercellular signaling and adhesion but previous results have shown that protein structures, interactions and conformational changes are the driving forces.

In this project we use two important protein signaling and adhesion systems, Notch and Contactin, to better understand the molecular mechanisms that underlie signaling and adhesion. The Notch and Contactin family of proteins play key roles in the development and function of several organs including our nervous system. Aberrant function of these proteins leads to the development of cancers and neurological disorders. Questions that we are addressing are: How do proteins interact in isolation and in a membrane setting? How does ligand binding induce receptor signaling? How are signaling and adhesion assemblies formed? These detailed mechanistic and structural insights will provide a molecular basis for understanding signaling and adhesion events. And ultimately these insights will help in the development of therapeutics that target diseases caused by malfunction of adhesion processes and intercellular signaling.

Work performed

In the first half of the project the research team has been formed, and research in this project has taken off, gained momentum and is now in full swing. We have established the production and purification of most players involved. The proteins are often large, consist of multiple domains (up to 40 for the Notch extracellular segment) and are posttranslationally modified. We therefore make use of tissue culture (HEK293 cell) that is ideally suited for these samples and enables to provide high quality proteins. We have determined interactions between proteins and established the oligomeric state for many of the samples. Structural studies have revealed the first detailed insights and have indicated avenues to further improve the samples.

Final results

The structural insights that we have obtained are novel. Also, the interaction experiments have provided information on new interactions. In the next half of the project we will use these new insights to further detail the intricacies of intercellular adhesion and signaling in our nervous system.