PINK1 is a mitochondrial serine/threonine-protein kinase that protects cells from stress-induced mitochondrial dysfunction. The precursor of PINK1 (65 kDa) is synthesized in the cytosol and is imported into the outer membrane of mitochondria. PINK1 is further transferred into the inner membrane where it is cleaved into a 52 kDa mature form. The half life of the mature form of PINK1 is very short and it was proposed that the proteasome is involved in its degradation. The gene of PINK1 maps to chromosome 1p36.12. Two alternatively spliced variants exist, the shorter isoform (30 kDa) produced by alternative splicing. Mutations in the PINK1 gene cause autosomal recessive early-onset Parkinson's disease.