Biology subjects

Hsu, C.-h.

Publications and source records attributed to Hsu, C.-h..

2 recordsLinked to original sources

bioRxiv2026

EOLA1, a novel mitochondria-localized protein critical for heart functions via regulating mitochondrial translation

Mitochondria possess their own mRNA translation system, mediated by specialized mitoribosomes. Dysregulation of mitochondrial translation disrupts metabolic homeostasis and is linked to various pathologies, including metabolic syndromes, neurological disorders, and cardiac diseases. Using CRISPR/Cas9 screening, we identified EOLA1 (endothelial-overexpressed lipopolysaccharide-associated factor 1) as a novel mitochondrial matrix protein essential for metabolic homeostasis. Knockout of Eola1 severely affects mitochondrial translation and consequently the oxidative phosphorylation in mammalian cells. Mechanistically, EOLA1 physically interacts with mitochondrial 12S ribosomal RNA (12S mt-rRNA) and the mitochondrial Tu translation elongation factor (TUFM), facilitating efficient translation elongation of mitochondrial-encoded mRNAs. Furthermore, genetic ablation of Eola1 in mice induced severe cardiac dysfunction, demonstrating its indispensable role in maintaining heart function through mitochondrial translation control. Together, our findings establish EOLA1 as a key regulator of mitochondrial translation via its interactions with 12S mt-rRNA and TUFM, highlighting its importance in cellular metabolism and a potential role in cardiac disease pathogenesis.

molecular biology↗

bioRxiv2020

METTL5, an 18S rRNA-specific m6A methyltransferase, modulates expression of stress response genes

RNA N6-methyladenosine (m6A) modification is present in different RNA molecules, including protein-coding mRNAs and non-coding RNAs such as ribosomal RNAs (rRNAs). Previous studies identified m6A in both the 18S and 28S rRNAs, but the roles of these methylation events are poorly understood due to the lack of knowledge of the responsible methyltransferases. Here, we report that mammalian METTL5, a member of a highly conserved methyltransferase family, specifically methylates adenosine 1832 (A1832) in the 18S rRNA in vivo and in vitro. We identify TRMT112 as a near stoichiometric partner of METTL5 important for the enzymatic activity of METTL5. By mapping the positions of translating ribosomes (Ribo-seq), we found translation of multiple stress response-related mRNAs, including Atf4 mRNA, is selectively reduced in the Mettl5 knockout (KO) mouse B16 melanoma cells. Atf4 is a key transcription factor that mediates the Integrated Stress Response (ISR), as exemplified by the Endoplasmic Reticulum (ER) stress. Consistently, transcription of ISR effector genes is reduced in Mettl5 KO cells during ER stress, suggesting a compromised ISR. Our findings reveal a new mechanism that regulates expression of stress response genes and suggest that chemical modifications of ribosomal RNAs may play a key role in selectively impacting translation and possibly ISR.

biochemistry↗