SLC25A45 is required for mitochondrial uptake of methylated basic amino acids and de novo carnitine biosynthesis (Part 2 = Interactome AP-MS Analysis)

ABSTRACT: Methylated amino acids accumulate upon the degradation of methylated proteins and are implicated in diverse metabolic and signalling pathways. Dimethylarginine inhibits nitric oxide synthase while trimethyllysine is metabolised in a compartmentalised manner to produce the amino acid derivative carnitine. Consequently, disturbed methylated amino acid homeostasis is associated with various disorders including cardiovascular disease and renal failure. Mitochondria are core processing hubs in conventional amino acid metabolism but how they interact with methylated amino acids is unclear. Here, we reveal that the orphan mitochondrial solute carrier SLC25A45 is required for the mitochondrial uptake of dimethylarginine and trimethyllysine. Characterisation of SLC25A45 identified a non-synonymous mutation of SLC25A45 near its C-terminus (R285C) that impacts solute carrier stability and associates with altered plasma methylated amino acid levels and cardiac alterations in men. Metabolic tracing of trimethyllysine reveals that SLC25A45 is essential for the de novo biosynthesis of carnitine. Suppression of SLC25A45 reduces intracellular acetylcarnitine levels and limits histone acetylation in carnitine-synthesising ovarian cancer cells. We propose that SLC25A45 is an essential mediator of compartmentalised methylated amino acid metabolism with diverse cellular roles that include epigenetic control.

INSTRUMENT(S):

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Pancreatic Adenocarcinoma Cell Line, Aspc-1 Cell, Pancreatic Duct

DISEASE(S): Pancreatic Cancer

SUBMITTER: Sergio Lilla  

LAB HEAD: Sara Rossana Zanivan

PROVIDER: PXD058579 | Pride | 2025-10-13

REPOSITORIES: Pride