Parkin, PINK1 and DJ1 as possible modulators of mTOR pathway in ganglioglioma

Ganglioglioma (GG) is a non-malignant tumor classified as G1 by the WHO. Although we currently know that the neoplasm may result from the hyperactivity of protein kinase B (PKB or Akt) or extracellular-regulated kinase (Erk), which upregulates mammalian target of rapamycin kinase (mTOR) and leads to translation of proteins responsible for cell cycle regulation, there are still many questions to be answered. In the current paper we try to analyze the link between GG formation and activity of three proteins known to play a role in neuroprotection (parkin, PINK1 and DJ1).

In our paper, we review the current information on the involvement of these proteins in the transmission of information in the cell and triggering various cell signals, like survival or apoptosis. We also review current literature data on involvement of parkin, DJ1 and PINK1 in the regulation of mTOR, the pathway probably contributing to the development of GG.

Parkin is an E3 ubiquitin ligase, shown to trigger proteasome-dependent degradation and autophagy, necessary for the maintenance of homeostasis in neurons. PINK1, a mitochondrial protein kinase, is required for mitochondrial maintenance and neuronal survival. DJ1 is a sensor of reactive oxygen species, and protects the cells against oxidative stress. Mutations in the genes encoding these three proteins are known to underlie autosomal recessive forms of Parkinson's disease, as well as other neurodegenerative and neuroinflammatory disorders.

It appears that mutations of parkin, PINK1 and DJ1 may result in the development of both neurodegeneration and tumors. Also, these proteins might be used as markers of disease, thus allowing better diagnosis and therapy.