The Ubiquitination of PINK1 Is Restricted to Its Mature 52-kDa Form

Publication date: 5 July 2017
Source:Cell Reports, Volume 20, Issue 1
Author(s): Yuhui Liu, Cristina Guardia-Laguarta, Jiang Yin, Hediye Erdjument-Bromage, Brittany Martin, Michael James, Xuejun Jiang, Serge Przedborski
Along with Parkin, PINK1 plays a critical role in maintaining mitochondrial quality control. Although PINK1 is expressed constitutively, its level is kept low in healthy mitochondria by polyubiquitination and ensuing proteasomal degradation of its mature, 52 kDa, form. We show here that the target of PINK1 polyubiquitination is the mature form and is mediated by ubiquitination of a conserved lysine at position 137. Notably, the full-length protein also contains Lys-137 but is not ubiquitinated. On the basis of our data, we propose that cleavage of full-length PINK1 at Phe-104 disrupts the major hydrophobic membrane-spanning domain in the protein, inducing a conformation change in the resultant mature form that exposes Lys-137 to the cytosol for subsequent modification by the ubiquitination machinery. Thus, the balance between the full-length and mature PINK1 allows its levels to be regulated via ubiquitination of the mature form and ensures that PINK1 functions as a mitochondrial quality control factor.

Graphical abstract

Teaser

PINK1 mutations cause Parkinson's disease. PINK1 is cleaved into a shorter 52-kDa form at the mitochondrial membrane, but regulation of the turnover of cleaved PINK1 is unknown. Liu et al. show that polyubiquitination of cleaved PINK1 regulates its degradation via the proteasome.


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