HEMK1 is an N5-glutamine methyltransferase that catalyzes methylation of the highly conserved GGQ motif in mitochondrial translation release factors (mtRFs), including MTRF1, MTRF1L, MRPL58, and MTRFR 1. This modification mirrors the bacterial PrmC enzyme's function in prokaryotic release factors and represents a conserved post-translational modification across prokaryotes and eukaryotes 1. Mechanistically, HEMK1-mediated GGQ methylation occurs in all four human mtRFs, as demonstrated by the absence of this modification in HEMK1-knockout cells 1. Despite its specific enzymatic activity, disruption of HEMK1 had minimal impact on cell growth, mitochondrial DNA copy number, membrane potential, and mitochondrial protein synthesis in HeLa cells under standard culture conditions, suggesting this modification is largely dispensable for basal cellular function 1. HEMK1 has been identified as a co-expressed gene associated with FHIT in lung adenocarcinoma 2 and as a hub gene in coronary artery disease pathogenesis networks 3. Additionally, HEMK1 expression is upregulated in allergen-specific T cells from peanut-allergic patients and appears in disease-relevant genetic networks for type 1 and 2 diabetes 4 5. These associations suggest potential roles beyond mitochondrial translation termination, though clinical significance remains to be fully elucidated.