Analysis of the regulatory and catalytic domains of PTEN-induced kinase-1 (PINK1)

Abstract

Mutations of the phosphatase and tensin homolog (PTEN)-induced kinase 1 (PINK1) gene can cause early-onset familial Parkinson disease (PD). PINK1 encodes a neuroprotective protein kinase localized at the mitochondria, and its involvement in regulating mitochondrial dynamics, trafficking, structure, and function is well documented. Owing to the lack of information on structure and biochemical properties for PINK1, exactly how PINK1 exerts its neuroprotective function and how the PD-causative mutations impact on PINK1 structure and function remain unclear. As an approach to address these questions, we conducted bioinformatic analyses of the mitochondrial targeting, the transmembrane, and kinase domains of PINK1 to predict the motifs governing its regulation and function. Our report sheds light on how PINK1 is targeted to the mitochondria and how PINK1 is cleaved by mitochondrial peptidases. Moreover, it includes a potential optimal phosphorylation sequence preferred by the PINK1 kinase domain. On the basis of the results of our analyses, we predict how the PD-causative mutations affect processing of PINK1 in the mitochondria, PINK1 kinase activity, and substrate specificity. In summary, our results provide a conceptual framework for future investigation of the structural and biochemical basis of regulation and the neuroprotective mechanism of PINK1.