A mutation in a mitochondrial protein leads to Abeta accumulation

A mutation in a mitochondrial protein leads to Abeta accumulation

Alzheimer's disease is caused by protein (amyloid) deposition in the brain. New research at the University of Bergen (UiB) and Haukeland University Hospital shows that the protein PITRM1, which is found in mitochondria, otherwise known as the powerhouses of the cell, may be involved in the development of the disease.

"When the level of PITRM1 in the cells decreases, this leads to an increase in the deposition of protein sediment in the brain," says the researcher.

The group has investigated a family with a gene defect that leads to reduced amounts of PITRM1. The family suffered major physical and psychological problems.

"The family had reduced amounts of this PITRM1 protein and became increasingly ill. Scans of their brains confirmed the damage and when we tested mice with the same loss of PITRM1, these too had neurological problems and protein deposition in the brain," says the author.

Authors show the presence of Abeta in the mitochondria. PITRM1 is the peptidase specifically dedicated to Aβ clearance within mitochondria and that even partial impairment of this function, caused by either instability of a mutant variant  (family) or hemizygosity (the Pitrm1+/ mouse), can determine neurodegeneration with accumulation of amyloidotic Aβ, directly linking the latter with abnormal mitochondrial proteostasis.

"The results conclude a long discussion about the relationship between mitochondria and accumulation of amyloid in the brain. We have found that mitochondria play a crucial role in the process of protein deposition," says the author.