Parkin and its Role in Skeletal Muscle Function

Autophagy is a major intracellular degradation system involving the delivery of long-lived cellular constituents to lysosomes for degradation. Under basal conditions, autophagy assists in the maintenance of cellular homeostasis and is elevated when cellular energetic demands are increased. When mitochondria are dysfunctional and unable to assist in sustaining cellular requirements, mitophagy is activated to selectively degrade damaged mitochondria. Parkin has been implicated in neuronal mitophagy, but little is known about its function in muscle. Young (3 months) Parkin deficient (KO) mice were compared to wild-type (WT) animals to examine how endogenous Parkin levels mediate mitophagy and mitochondrial content in mammalian muscle. Our analysis revealed that Parkin KO mice exhibited no muscle mass differences in their quadriceps and tibialis anterior when compared to WT mice. This was accompanied by no differences in mitochondrial yield and whole muscle cytochrome c oxidase activity. When mitochondrial fu...