An insight into autism and other brain disorders

Turns out, a protein that lingers too long on the membrane may compromise the connections, or synapses, between cells in the brain.

In a new study, Rockefeller scientist Mary E. Hatten and research associate Hourinaz Behesti demonstrated that the protein ASTN2 helps move proteins away from the membrane in a timely fashion. The researchers also propose a mechanism by which ASTN2 defects lead to neurodevelopmental disorders such as autism and intellectual disabilities.

Hatten, the Frederick P. Rose Professor, has demonstrated that the protein ASTN2 acts as such a trafficker during cell migration in early development.

Specifically, the protein appears to be disproportionally expressed in the cerebellum- a brain region that some researchers suspect may govern complex aspects of cognition, in addition to its more-established role in regulating movement.

The researchers used a special microscopy technique to determine where ASTN2 is expressed in the mouse cerebellum. They found that it appears primarily in components of neurons responsible for moving proteins around, and they identified a collection of molecules that attach to ASTN2. These "binding partners" included proteins involved in synapse formation and protein trafficking.

"Our data suggest that people who have mutations in ASTN2 make less of the protein, which leads to slower or weaker synapses," says Behesti. The researchers propose that without sufficient ASTN2, proteins accumulate on the cell surface, which hinders neuronal connections and communication.

This research supports a broader view that the disruption of surface protein composition may underlie a number of neurodevelopmental disorders. It also points to the cerebellum as a potentially fruitful research subject for understanding these conditions.

The full findings are present in the Proceedings of the National Academy of Sciences.