Dec. 6 (HealthDay News) -- Problems involving a brain protein called CASK and an enzyme called Cdk5 may be part of the cause of autism and other brain disorders, say researchers at Massachusetts Institute for Technology's Picower Institute for Learning and Memory.

CASK plays a major role in the development of synapses, which send and receive signals between neurons and underlie the ability to learn and remember. Improperly formed synapses can cause mental retardation, and mutations in genes encoding certain synaptic proteins are associated with autism, according to background information in the study.

In this study, the MIT researchers looked at how a kinase (an enzyme that change proteins) called Cdk5 interacts with CASK.

"We found that Cdk5 is critical for recruiting CASK to do its job for developing synapses," Li-Huei Tsai, a professor of neuroscience, said in a prepared statement. "Without Cdk5, CASK was not in the right place at the right time, and failed to interact with essential presynaptic components. This, in turn, led to problems with calcium influx."

The flow of calcium in and out of neurons affects the nervous system's development and its ability to change in response to experience.

"There are still a lot of unknowns. Causes for psychiatric disorders are still very unclear, but accumulating evidence strongly suggests that alterations in the synaptogenesis program can lead to these serious diseases," Tsai said.

The study appears in the Dec. 6 issue of the journal Neuron.

SOURCE: MIT news release, Dec. 5, 2007