Dual role of USP 30 in controlling basal pexophagy and mitophagy

USP 30 is an integral protein of the outer mitochondrial membrane that counteracts PINK 1 and Parkin‐dependent mitophagy following acute mitochondrial depolarisation. Here, we use two distinct mitophagy reporter systems to reveal tonic suppression by USP 30, of a PINK 1‐dependent component of basal mitophagy in cells lacking detectable Parkin. We propose that USP 30 acts upstream of PINK 1 through modulation of PINK 1‐substrate availability and thereby determines the potential for mitophagy initiation. We further show that a fraction of endogenous USP 30 is independently targeted to peroxisomes where it regulates basal pexophagy in a PINK 1‐ and Parkin‐independent manner. Thus, we reveal a critical role of USP 30 in the clearance of the two major sources of ROS in mammalian cells and in the regulation of both a PINK 1‐dependent and a PINK 1‐independent selective autophagy pathway.