The mutant ARR4 protein is degraded via the proteasome pathway.
In eukaryotic cells, protein abnormalities which lead to incorrect folding or protein aggregation may be eliminated via the proteasome or lysosome degradation pathways. In order to determine whether abnormal ARR4 proteins could be degraded through those pathways transfected cells were pretreated with either a proteasomal or lysosomal inhibitor. Compared to wild-type ARR4 proteins, the MG-132 proteasome inhibitor could significantly restore mutant ARR4 protein levels (Figure 5A). In contrast, chloroquine, a lysosomal inhibitor, was incapable of restoring mutant protein concentrations (Figure 5B).