Here is a paper elucidating PSD, postsynaptic density, proteins and their potential function in health and disease.
ScienceDaily (Dec. 20, 2010) — Scientists have isolated a set of proteins that accounts for over 130 brain diseases, including diseases such as Alzheimer's disease, Parkinson's disease, epilepsies and forms of autism and learning disability. The team showed that the protein machinery has changed relatively little during evolution, suggesting that the behaviors governed by and the diseases associated with these proteins have not changed significantly over many millions of years. The findings open several new paths toward tackling these diseases.
The brain is the most complex organ in the body with millions of nerve cells connected by billions of synapses. Within each synapse is a set of proteins, which, like the components of an engine, bind together to build a molecular machine called the postsynaptic density -- also known as the PSD. Although studies of animal synapses have indicated that the PSD could be important in human diseases and behaviour, surprisingly little was known about it in humans.
A team of scientists, led by Professor Seth Grant at the Wellcome Trust Sanger Institute and Edinburgh University, have extracted the PSDs from synapses of patients undergoing brain surgery and discovered their molecular components using a method known as proteomics. This revealed that 1461 proteins, each one encoded by a different gene, are found in human synapses. This has made it possible, for the first time, to systematically identify the diseases that affect human synapses and provides a new way to study the evolution of the brain and behaviour.
"We found that over 130 brain diseases involve the PSD -- far more than expected," says Professor Grant.
"Our findings have shown that the human PSD is at centre stage of a large range of human diseases affecting many millions of people," says Professor Grant.
Genetic Basis of Brain Diseases: Set of Proteins Account for Over 130 Brain Diseases