The endoplasmic reticulum/mitochondria interface: a subcellular platform for the orchestration of the functions of the PINK1-Parkin pathway?

Mitochondrial dysfunction is a hallmark of both idiopathic and familial Parkinson's disease (PD). Mutations in the PARK2 and PARK6 genes, coding for the cytosolic E3 ubiquitin protein ligase Parkin and the mitochondrial serine/threonine kinase PINK1 [phosphatase and tensin homologue (PTEN)-induced putative kinase 1], lead to clinically similar early-onset Parkinsonian syndromes. PINK1 and Parkin cooperate within a conserved pathway to preserve mitochondrial quality through the regulation of a variety of processes, including mitochondrial dynamics, transport, bioenergetics, biogenesis and turnover. The molecular mechanisms behind the orchestration of this plethora of functions remain poorly understood. In the present review, we emphasize the functional overlap between the PINK1-Parkin pathway and the endoplasmic reticulum (ER)-mitochondria interface, a subcellular compartment critically involved in neurodegeneration. We discuss how this compartment may constitute a hub for the spatiotemporal organization of the activities of the PINK1-Parkin pathway.