Food for Thought

A team from the Institute for Research in Biomedicine (IRB Barcelona) led by Eduardo Soriano, professor and director of the Department of Cell Biology of the UB, has published a study in the journal Nature Communications describing a new family of six genes that regulate the movement and position of mitochondria in neurons. It is a cluster of six genes that may be altered in neurological conditions, such as Parkinson’s and Charcot-Marie-Tooth disease, which are caused by alterations of genes that control mitochondrial transport, a process that provides the energy required for cell function. Jordi Garcia-Fernàndez, professor of the Department of Genetics and member of the Institute of Biomedicine of the University of Barcelona (IBUB), affiliated centre to the Barcelona Knowledge Campus (BKC), a health campus of international excellence, has also taken part in the study, among other authors.

By means of comparative genomic analyses, the scientific team has discovered that these genes are found only in more evolved mammals, the so-called eutharia, namely with internal fertilization and development. According to Eduardo Soriano, “this finding indicates the relevance of mitochondrial biology. When the brain evolved in size, function and structure, the mitochondrial transport process also became more complex and probably required additional regulatory mechanisms”. Jordi Garcia-Fernàndez adds that “likewise, given the origin of the gene cluster, in the transition between primitive mammals such as marsupials (kangaroos) and the other placental mammals, it is tempting to propose the hypothesis that its origin is linked to the increased complexity of the cerebral cortex in the evolutionary lineage that leads to humans”.

Correct brain function is highly energy-demanding. However, this energy must be finely distributed throughout neurons —cells that have ramifications that can reach up to tens of centimetres in length, from the brain to the limbs. This cluster of genes forms part of the “wheel” machinery of mitochondria and regulates the localization of each cell on the basis of its energy requirements. “These genes would be like an extra control in cellular mitochondrial trafficking and they interact with the major proteins associated with the regulation of mitochondrial transport”, explains Soriano.

Another striking characteristic of these new proteins is that they are found both in mitochondria and in the cell nucleus, where their function is unknown. “They may also be involved in the regulation of gene expression, a possibility that we are now studying”. In addition to their potential involvement in brain pathologies, the researchers believe that these proteins may be related to metabolic diseases and cancer.

This study has been performed in collaboration with the teams headed by Jordi Garcia-Fernàndez, from the UB, Ramón Trullás and Javier García-Sancho, both from the CSIC, and Antoni L. Andreu, from the Hospital de la Vall d´Hebron.