PINK1
PINK1 (PTEN-induced kinase 1) is a mitochondrial serine/threonine kinase that orchestrates mitochondrial quality control, and its loss causes autosomal-recessive Parkinson disease at the PARK6 locus. Under depolarized conditions, PINK1 accumulates on the outer mitochondrial membrane and phosphorylates both ubiquitin and the E3 ligase Parkin at Ser65, initiating feedforward amplification that tags damaged mitochondria with phospho-ubiquitin chains and recruits autophagy adaptors for mitophagy. PINK1 also supports mitochondrial function and stress responses independent of Parkin. The phospho-ubiquitin pathway has reshaped understanding of Parkinson disease mechanisms and is a therapeutic target. Recombinant PINK1 is used for mitophagy assays, Parkin activation studies and inhibitor screening.
