Physical Society Colloquium

Can statistical mechanics explain a human disease?

Gary Brouhard

Department of Biology
McGill Univeristy

Double cortex syndrome is an inherited brain disorder that causes epilepsy and mental retardation. The disease arises from mutations in the gene for Doublecortin, a protein expressed in newborn neurons. Doublecortin associates with microtubules: long, slender polymers of the protein tubulin that form part of the cytoskeleton. Using single-molecule biophysics, we have discovered that Doublecortin binds to microtubules in a highly cooperative manner characterized by strong nearest-neighbor interactions. Mutations found in human patients disrupt this cooperativity. We are exploring the use of Ising-type models to describe this cooperative binding. The breakdown in cooperativity found in mutated forms of Doublecortin can be described with the parameters of the Ising-type models, indicating that models based in statistical mechanics can be applied to the mechanism of a complex human disease.