NKF2
Novel kinase family 2 effectively consists of one well-characterized enzyme, PINK1 (PTEN-induced kinase 1), whose distant relatives could not be assigned elsewhere in the kinome. PINK1 carries an N-terminal mitochondrial targeting sequence, a transmembrane segment, a serine/threonine kinase domain and a C-terminal region. In healthy mitochondria it is imported and degraded, but on depolarization it accumulates on the outer membrane, where it phosphorylates ubiquitin and the E3 ligase Parkin at Ser65, launching mitophagy of the damaged organelle. Loss-of-function PINK1 mutations cause autosomal recessive early-onset Parkinson disease, and the kinase is also implicated in mitochondrial quality control in neurons and in innate immune signaling.
