A team of researchers from the University of California at Davis (USA) claims to have deciphered the function of mysterious groups of proteins found in neurons in the hippocampus, the region of the brain that plays an important role in learning and memory.
It was known that the alteration of these groups can cause serious neurological disorders, but it was not clear why. But now it has been discovered that these sets of proteins are calcium signaling “hot spots”, which play a crucial role in the activation of gene transcription.
Transcription allows the neuron’s DNA to be converted into strands of RNA, which are then used for the formation of proteins necessary for cells. The authors of the new study, published recently in the journal PNAS, looked at protein clusters in mice and noted that there are between 50 and 100 such clusters in a single neuron.
Fundamental to learning and memory
These groups are formed by a protein, which allows potassium ions to pass through the membranes (potassium channel), and by calcium channels. Calcium channels allow this chemical element to filter into cells, where it triggers various physiological reactions. ‘We have known for a long time about the function of other types of ion channel groups, for example those in synapses. But it was not known what role these much larger structures of the cell body play in the physiology of the neuron, ‘said study co-author Professor James Trimmer.
Scientists deciphered the role of “hot spots” by separating the calcium channel from the potassium channel clusters. ‘A key finding was that this process blocked calcium-activated gene expression. This suggests that the association between calcium and potassium channels in these groups is important for neuronal function” clarified Nicholas Vierra, lead author of the research.
As a result of this separation, the process known as excitation-transcription coupling, which links changes in neuronal electrical activity with changes in gene expression, was inactivated. “We found that interfering with the calcium signaling proteins located in these unusual clusters basically eliminates the excitation-transcription connection, which is critical for learning, memory, and other forms of neural plasticity,” Trimmer said. The scientists hope their findings will lead to new research on the role of signaling in brain function, and will aid in the development of new types of therapies.