Phosphorylation of Parkin at serine 131 by p38 MAPK promotes mitochondrial dysfunction and neuronal death in mutant A53T alpha-synuclein model of Parkinson's disease

alpha-synuclein abnormal accumulation and mitochondria dysfunction are involved in the pathogenesis of Parkinson's disease. Selective autophagy of mitochondria (mitophagy) is a crucial component of the network controlling the mitochondrial homeostasis. However, the underlying mechanism that mutant a-synuclein induces mitochondrial abnormality through mitophagy impairment is not fully understood. Here, we showed that mutant A53T alpha-synuclein accumulation impaired mitochondrial function and Parkin-mediated mitophgy in alpha-synucleinA53T model. alpha-synucleinA53T overexpression caused p38 MAPK activation, then p38 MAPK directly phosphorylated Parkin at serine 131 to disrupt the Parkin's protective function. The p38 MAPK inhibition significantly reduced cellular apoptosis, restored mitochondrial membrane potential as well as increased synaptic density both in SN4741 cells and primary midbrain neurons. These findings show that the p38 MAPK-Parkin signaling pathway regulates mitochondrial homeostasis and neuronal degeneration, which may be a potential therapeutic strategy of PD via enhancing mitochondrial turn-over and maintenance.