Quantitative proteomics of synaptic and nonsynaptic mitochondria: insights for synaptic mitochondrial vulnerability.
Synaptic mitochondria are essential for maintaining calcium homeostasis and producing ATP, processes vital for neuronal integrity and synaptic transmission. Synaptic mitochondria exhibit increased oxidative damage during aging and are more vulnerable to calcium insult than nonsynaptic mitochondria. Why synaptic mitochondria are specifically more susceptible to cumulative damage remains to be determined. In this study, the generation of a super-SILAC mix that served as an appropriate internal standard for mouse brain mitochondria mass spectrometry based analysis allowed for the quantification of the proteomic differences between synaptic and nonsynaptic mitochondria isolated from 10-month-old mice. We identified a total of 2260 common proteins between synaptic and nonsynaptic mitochondria of which 1629 were annotated as mitochondrial. Quantitative proteomic analysis of the proteins common between synaptic and nonsynaptic mitochondria revealed significant differential expression of 522 proteins involved in several pathways including oxidative phosphorylation, mitochondrial fission/fusion, calcium transport, and mitochondrial DNA replication and maintenance. In comparison to nonsynaptic mitochondria, synaptic mitochondria exhibited increased age-associated mitochondrial DNA deletions and decreased bioenergetic function. These findings provide insights into synaptic mitochondrial susceptibility to damage.
Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center , 985800 Nebraska Medical Center, Omaha, Nebraska 68198, United States.
Kelly L
KL
Stauch
Phillip R
PR
Purnell
Howard S
HS
Fox
D000328:Adult; D000818:Animals; D001921:Brain / Q000378:metabolism; D002460:Cell Line; D045744:Cell Line, Tumor; D002853:Chromatography, Liquid; D016000:Cluster Analysis; D006801:Humans; D015151:Immunoblotting; D007553:Isotope Labeling / Q000379:methods; D008297:Male; D008810:Mice, Inbred C57BL; D008854:Microscopy, Electron; D008928:Mitochondria / Q000378:metabolism* / Q000648:ultrastructure; D024101:Mitochondrial Proteins / Q000145:classification / Q000378:metabolism*; D025341:Principal Component Analysis; D020543:Proteome / Q000145:classification / Q000378:metabolism*; D040901:Proteomics / Q000379:methods*; D013569:Synapses / Q000378:metabolism*; D053719:Tandem Mass Spectrometry
D024101:Mitochondrial Proteins; D020543:Proteome