Complex formation of EphB1/Nck/Caskin1 leads to tyrosine phosphorylation and structural changes of the Caskin1 SH3 domain.

Background: Scaffold proteins have an important role in the regulation of signal propagation. These proteins do not possess any enzymatic activity but can contribute to the formation of multiprotein complexes. Although scaffold proteins are present in all cell types, the nervous system contains them in the largest amount.

High levels of structural disorder in scaffold proteins as exemplified by a novel neuronal protein, CASK-interactive protein1.

CASK-interactive protein1 is a newly recognized post-synaptic density protein in mammalian neurons. Although its N-terminal region contains several well-known functional domains, its entire C-terminal proline-rich region of 800 amino acids lacks detectable sequence homology to any previously characterized protein. We used multiple techniques for the structural characterization of this region and its three fragments.