Before revision:  We also consider receptor cluster formation on individual peroxisomes with enhanced levels of ubiquitinand find that size-selectivity, but not cluster formation , is suppressed. Thus, our selectivity mechanism does not hinder selection of individual URLanelles via enhanced ubiquitination. NBR1 cluster formation provides a viable physical mechanism for all-or-none substrate selectivity in pexophagy .
After revision:  We also consider receptor cluster formation on individual peroxisomes with enhanced levels of ubiquitinand find that size-selectivity, but not cluster formation . Our proposed selectivity mechanism thus allows all URLanelles to be degraded, while otherwise selecting only a portion URLanelles for degradation .