Abstract
Glutaric aciduria type 1 (GA1) is an inherited neurometabolic disorder caused by mutations in the GCDH gene encoding glutaryl-CoA dehydrogenase (GCDH), which forms homo- and heteromeric complexes in the mitochondrial matrix. GA1 patients are prone to the development of encephalopathic crises which lead to an irreversible disabling dystonic movement disorder. The clinical and biochemical manifestations of GA1 vary considerably and lack correlations to the genotype. Using an affinity chromatography approach we report here for the first time on the identification of mitochondrial proteins interacting directly with GCDH. Among others, dihydrolipoamide S-succinyltransferase (DLST) involved in the formation of glutaryl-CoA, and the β-subunit of the electron transfer flavoprotein (ETFB) serving as electron acceptor, were identified as GCDH binding partners. We have adapted the yellow fluorescent protein-based fragment complementation assay and visualized the oligomerization of GCDH as well as its direct interaction with DLST and ETFB in mitochondria of living cells. These data suggest that GCDH is a constituent of multimeric mitochondrial dehydrogenase complexes, and the characterization of their interrelated functions may provide new insights into the regulation of lysine oxidation and the pathophysiology of GA1.
Highlights
The inherited neurodegenerative disorder glutaric aciduria type 1 (GA1, OMIM 231670) is caused by mutations in the gene for the mitochondrial matrix enzyme glutaryl-CoA dehydrogenase (GCDH, E.C. 1.3.99.7)
Mass spectrometric analysis of polypeptides eluted with high salt buffer and digested with trypsin resulted in the identification of five mitochondrial matrix proteins, two inner mitochondrial membrane proteins and three peroxisomal proteins (Table 1; Table S2)
Dihydrolipoamide S-succinyltransferase (DLST) and electron transfer flavoprotein subunit beta (ETFB) have been studied in more detail in this study because both proteins are directly involved in the degradation pathway of lysine and tryptophan
Summary
The inherited neurodegenerative disorder glutaric aciduria type 1 (GA1, OMIM 231670) is caused by mutations in the gene for the mitochondrial matrix enzyme glutaryl-CoA dehydrogenase (GCDH, E.C. 1.3.99.7). GCDH belongs to the acyl-CoA dehydrogenase family of mitochondrial flavoproteins and catalyzes the oxidative decarboxylation of glutaryl-CoA in the degradative pathway of the amino acids lysine, hydroxylysine and tryptophan [1,2]. Mutations in the GCDH gene lead to formation and accumulation of the dicarboxylates glutaric acid (GA) and 3-hydroxyglutaric acid (3OHGA) in tissues and body fluids. More than 150 different mutations in the GCDH gene with predominance in specific populations have been described, which lead to a wide spectrum of clinical symptoms in GA1 patients ranging from an asymptomatic course to severe disabling dystonia [8,9,10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
