Prkn Knockout mouse models

Parkin, the product of mouse Prkn and ortholog of human PRKN, is an RBR-class E3 ubiquitin ligase built from a ubiquitin-like domain followed by RING0, RING1, IBR, and RING2 modules that hold the catalytic Cys431 in an autoinhibited conformation. Binding of PINK1-generated phospho-Ser65 ubiquitin plus phosphorylation of the parkin Ubl domain releases autoinhibition, allowing thioester transfer and amplification of ubiquitin chains on outer membrane substrates including MFN1, MFN2, and MIRO, committing damaged mitochondria to mitophagy. Recessive exon deletions and missense alleles cause juvenile parkinsonism without Lewy pathology. Because Prkn nulls are viable and lack nigral cell loss, informative designs include conditional null combined with mitochondrial stress, catalytically dead C431S knockins that separate ligase activity from scaffolding, constitutively active W403A-type alleles, and humanization for activator screening. Match allele class to endpoint using dopaminergic Cre drivers and mitophagy reporters rather than expecting spontaneous degeneration.

Whole body loss of Prkn gives the clearest readout when the question is whether the gene is required at all. Follow up tissue work can still move to a conditional allele if lethality or compensation appears.